Welcome! The first few chapters are more character studies while from Chapter 7 they are full blown one shots around 1000-2000 words.
I hope you enjoy :)
Sherlock and 'Anthea' have a mutual respect for one another. Sherlock highly regards the fact that she is able to keep her brother organised and in check which should be near impossible with his personality and all the things he has going on. Also, he has seen what she can do to a man with only a hard kick, a stiletto heel and a hair clip.
'Anthea' admires the consulting detective for his intelligence. Also if her boss, a man she respects so deeply, can spend so many resources and emotional energy on keeping him safe he must have some redeeming features and be part of the greater good, no matter his methods. She has also seen that he can do real good in the world when he puts his mind to it.
They express their positive feelings for each other by providing snark and sarcastic comments from one corner and from the other, small easy sentences and knowing smirks like he is being adorable. She knows it really gets to him when he's treated like a child.
Mycroft stays out of all of this but secretly approves, believing it is good for both of them. However, sometimes he can't help the small smile and nod at his assistant when she manages to silence his brother with a look. Not many people have the skill to do that.