Thanks each.
Celia - yes, I've trawled the web but no luck.
Mel - thanks for the pointer, that hadn't occurred to me (slaps forehead!)
Ricki - yes, I'd tried there. I'm afraid Derby St. wasn't very photogenic!
The thing is, I must have used Derby St. as a shortcut loads of times in my youth without ever knowing there was a strong family connection and paying it no attention. I even remember once turning into it by a few feet on my moped (I think I was too young for a proper motorbike license) to park outside Alec Green's and a young plod telling me off because it was a play street. Just how young must that copper have been for a callow 16 year old to think him young. Funny the things you remember.
Next time I'm in Birkenhead, I foresee a library visit. I've always liked that library building.
Les