Lovely look at a pairing that I've always liked on screen and in fic. Your final paragraph make me nod and get a little misty eyed too.

I've written them a few times but never really all that deeply; closest I came was in a post-Chosen fic, Love it Was Indeed (http://www.janedavitt.com/Love.html)

I don't know why it's not written more; Giles spent more time with Anya than anyone else during the time he owned the shop; so much to work with there.