Hi Barry, we must have coincided, I attended the Assembly Rooms, and sang there many times, Derek once even booked me to do an evening. The Surbiton Crescent venue you mentioned was I think, on the corner of Surbiton Road and Penrhyn Road, with Southsea Road along the side of it. I looked on Google maps, and it's no longer a pub. I remember The Cricketers, upstairs from the public bar. I remember bodily carrying a friend of mine who was in a wheelchair, up those stairs, with help of course. health and Safety reg's nowadays would stop that happening.
Had many good times there, and I am still in contact with one of the regular singers, Hector Gilchrist.