the 28 route was covered by Liverpool St and Highgate Road. After Highgate Rd was closed, it appears Lea Hall also got involved.
Of the pictures I've been through, these are my thoughts"
2428,1925,1888,1890 and 2859 Liverpool St
1783,2832,1809 Lea Hall.
2428 is the best picture I have,all the other are pretty blurry, although 1783 has an interesting blind of 28F - Kingstanding Road and another road underneath with I cannot make out. It is very obviously at Lea Hall.
I cant't think I have any other pictures of buses from either garage with a 28 destination but will over the course of the next little while have a look, assuming most of these pictures would relate to the early 60's when I was fairly familiar with which stock was at which garages.