Thank you for the information. I would have been around 10 when I got the bike so that ties in on the timescale. I've no idea of value or where I could sell it. I've attached a couple more photos.Until recently I worked with Alexis Brassey at a law firm in London. His father owned the shop which I believe was on Walton Road in the 1970s and 1980s. I understand that apart from selling mass produced bikes he also bought in frames to label with his own decals. Given the lugwork I’d say this frame is mid 1970s.
I've no idea of value or where I could sell it.