Photography ban...?

[Valandil]

RE: Photography ban...?
I've been stopped by a plain clothes police officer before for photographing a bus.
He demanded that I show him the photograph and other photographs of buses I'd taken recently, presumably to show that I am an enthusiast and wasn't just interested in that particular bus.
He took my name and address then followed me in his car (I was on foot).
I don't know why he needed my name and address, but suspect I'm on some kind of database for something now.

I have thought many times about complaining or going to a police help desk to ask if the police officer was entitled to do all of this, but have never done so for fear of reigniting the whole issue.
By the way, this wasn't in Merseyside but was elsewhere in the North West.
EDIT: I should also clarify that this wasn't at a bus station and was just on a normal road.