Disclaimer: I sort of go backwards. I actually had to do a bit of research, as I'm not British, and needed to figure out a Britishy-sounding place for Dudley to live, with a reachable distance to London and Kings Cross Station.
The house on Upper Lattimore Road in Saint Albans, Hertfordshire, was mostly bought and paid for by Colette Bottlesworth Dursley's parents. Much like their daughter, they were round, good-hearted, and of open natures. They were certainly like none Dudley had known in Little Whinging, for there, gossip and competition reinforced barriers among neighbors, isolating their little secrets, and maintaining the illusion of absolute mundanity.
Dudley vowed to repay them every bit, until his business aspirations could be realized. Before Colette, much of his money was blown on an over-priced flat, a brand-new car, and gleaming electronic gadgets he had no use for. After Colette, his entire world had changed. If having her meant parting himself from the vestiges of Old Dudley, then so be it. He had long lost any pleasure he gained from such things when he found himself desperately alone. The only one among his friends not in University, the name 'Big D' failed to tout the dread it once had among the professional heavy-weights he was then surrounded by. Like said heavy-weights, Colette cast a bland eye on him and his possessions, her affections waning like so much whiskey out of Dudley's bottle.
One day, after sifting through empty take-out boxes in search of the remote to Dudley's plasma screen, she tossed her hands in the air, defeated by filth.
"We can't afford a life together if you continue to spend money like a child. I think it's time you did some maturing." And with that, she was gone. It hardly took a fortnight for Dudley to plot out his next course of action.
He kept in contact with his old childhood friend Piers, who had just finished University and was thankfully still a bachelor. Piers thought it a fetching idea to move into a modest two bedroom flat on the dodgy end of London with him. The non-broken and non-lost items of excess were pawned off, but he retained his car. His father always told him that the car made the man. He took on more matches, became something of a local celebrity, and saved what he could to realize his dreams. The first of which being wedded bliss with one Colette. The second being a butcher shop, where his love of food and violence could be gracefully employed into one noble skill. The property was payed for, along with the equipment, counters, and the certification classes, of course. Shortly afterwards, Colette arrived through the doors of his new establishment and agreed to set the date.
Thus did true love bloom over flank steak.
Though nearly destitute, Dudley's business flourished. If not for the birth of Dana, The Bottlesworths would have been compensated in full for their home. And then they had little Dale four years later, which set them further back. The Bottlesworths thought of their grandchildren as compensation enough, and quite forgot about the debt. Dudley however, always so used to taking and having, could not bring himself to do so with the Bottlesworths. He learned many years ago that to abuse the charity of the Kind meant a lifetime of regret for him. If it wasn't for the kindness of a certain cousin, he would be nothing. A body that only caged an empty heart; one that had never been used to love. He considered the many ways he might repay Harry, but the act could not be matched.
The house on Upper Lattimore Road was indisputably lived-in. Dudley, who failed to inherit his mother's incessant cleanliness, never noticed when the house fell into disarray. Colette did all she could, but Dana and Dale proved to be little tornadoes; anything that stood erect would soon be lying prone after one or both had passed it. Many children's books were scattered around the once "good living-room" floor. The "family room" was more of a travesty, with unwashable pen markings in some kind of runes looped along the pale blue walls, stuffing protruding out of cushions, and teen magazines as the only available reading material on their coffee table. Dale's disregard for order was legend. At only four feet tall, and weighing the same as a loaf of bread (a particularly dense loaf that only Colette could bake), a room could be left in chaos with his only passing through it.
Upon finding her new jumper in tatters, Dana thundered noisily as only an embittered teenager can.
"What in the bloody hell did you do!!!!!!!!!!!!!!!!"
"I haven't been in your room, you banshee!" Cried Dale, his green eyes flashing a warning.
"My new jumper with the v-neck! I was going to wear it to Jeanette's!"
"That jumper's so tarty, it probably came like that!" Then a scuffle commenced. The thunder rolled above the kitchen, jostling the light fixtures. Dudley, still in a bloodied smock, put down his paper and shook his head exasperatedly. Colette tasted the tomato sauce simmering on the stove. "It needs oregano." She followed this with, "We're sending you to live with grandma and grandpa Dursley!" The fighting abated marginally, only cuss words were being loudly hurled back and forth.
"I'll put an end to it!" Dudley harrumphed.
"Thank you, darling. And tell them to wash their filthy little hands for dinner."
"Will do." Blood-covered and all, he set out to intimidate his children.
"What's all this about!" He shouted. Dana, splotchy and venomous, breathed heavily on the floor. Dale, red and near tears, puffed out his lips beside her.
"Daddy, he ruined my--"
"Jumper, yes, I heard all about it!" Dudley interrupted.
"No I didn't! I wasn't even in your room!"
"You did! You're always doing weird things. He should be in Saint Brutus's!"
"Not another word out of either of you! Dana, you had no business buyin' that thing without your mother's permission! Your blasted cat's been tearing up furniture again, so I'd say he's the likely culprit."
Dana, in all her adolescent anguish, fell into sobs, the unfairness choking her ability to speak proper English.
"Yaawaeestakeissiiiiiiide!"
"Quiet that nonsense and stop your fighting! If we didn't love you, we wouldn'ta bothered keepin' you. Now start getting along, or we'll rethink our decision!" Dudley shook the room with his steps and slammed the door in his wake. At the landing, he remembered the message he needed to relay.
"And wash your hands! We're havin' dinner!" Dale slid out of Dana's room, wiping a few escaped tears on the back of his hand.
"Dale, Dale, Dale." Dudley mussed his dark curly hair, so much like his mother's.
"Dad, I think Dana hates me." He pressed his little head into Dudley's squishy belly.
"Don't be daft, boy. Of course she doesn't hate you. She's just going through one of them feminine things, and once she grows up a little, she'll be great pals with you like she used to be."
Egbert the cat rubbed its side against Dale's shins, then pawed at Dana's door for entrance. He was given quiet admittance, and the door was returned to its frame.
"I didn't do it, Dad. Really, I didn't! But you know what?" He whispered conspiratorially.
"What's that?" Dudley bent down on his knee to properly listen.
"I thought about doing exactly that. When you made her take me to the shop, I saw her try it on. You can see her knockers. The man folding shirts was looking at them! I hated that shirt so much; I just wanted to tear it to pieces!"
Dudley hadn't realized that he stopped breathing.
"Dad, you're turning purple." Dale observed, tilting his head to the side. Dudley inhaled a massive breath of air, then coughed, his years of cigarette smoking, back to haunt him.
"Right, well, these things happen." Dudley said, lamely. Dale looked on, confused.
"No they don't. Well, they always happen to me, seems like." His face drooped.
"Well, you might take after some of my relatives, but you're just as normal a boy as any!" He laughed, patting him on the back. A few tricks here and there, doesn't mean he'll turn the house into a giant balloon one day. He reassured himself. It's bound to get into the genes a little; it don't mean nothin'.
Dale brightened, and happily descended the stairs. His hands remained unwashed.
"Don't mean nothin'." He said aloud, readying himself to invade his daughter's sanctuary.