Had a look today. It appears to be this building only, both sections of it. The numbers here are 1, 1a, 2, 2a for the southern section, and 3, 3a, 4, 4a for the northern section.

The buildings South of here are organised around a court, but the numbering appears to expand on Sunderland Road's: 42 to 73, if I recall correctly. It's distributed in a non-obvious way, between maisonettes (accessible from the ground) and flats (where each building has a single entrance to all flats, which presumably are at the top).

I'll return to map the numbers correctly.