I've probably said this before, but I've walked over that viaduct around 1970. The trains had stopped by then! We walked from Kemptown goods yard, through the tunnel, across the viaduct, and turned back when we actually saw trains!!
What a fascinating photo. Could it be a swimming pool? I used to look after these gardens throughout the 1980's but never thought they would have looked like this 50 years before.
Doing my Sherlock Holmes bit, people wearing flares, no goals or lines on the pitch - probably ploughed up but can't tell. South stand empty, £ 1.30 to get in.
My guess is Sunday morning, 6th May, 1979. The Goldstone party after getting promotion at Newcastle the day before and free to get in...
All the old black and white photos seem to show Brighton in a much better way I believe.
Just to see if it makes a difference, I've edited the above.
It seems to unify everything.
I lived at 81B Hanover Street from when I was born in 1956 until we moved to Woodingdean in 1963, in the top-right flat of the southern "Iron stairs" ones, opposite and along about twenty yards from the house in the photo. I must have walked up and down that alley thousands of times. I'm sure...