Hi, I've walked to Gabriel Street/Ackroyd Road from the station for the last few years and have never had any problems, also fairly late at night. Moved from NW3 to SE and liked it so much that I've just moved to a larger place a few streets away. A lot of people usually still get off both the trains and overground at night, even on the last train just before 1am, and pour into the surrounding streets. It's a safe and quiet area.

The restaurants and shops you mentioned are all very useful, in addition, there are Jam Circus (restaurant/bar, sometimes have live Jazz), Mr. Lawrences Wine Bar (lovely, as mentioned before) and the Brockley Jack (Pub, surprisingly nice food these days). Plus a good selection of restaurants and cafes in Forest Hill, all of which can easily be walked to from Gabriel Street. And hopefully, the Old Bank will re-open soon!

Shops - my personal favourite would be Jay's Budgens in Crofton Park - they management there is always friendly and helpful.