Just found the frame number - it is 18569 - from my investigations so far this could mean that the bike could be dated back to the 1950's perhaps? I found a site which said that the frame numbering is sequential and started at around 6000 in 1946 to 30000 in 1969 so I am assuming this could be an old gem.

Will take some photos and post to valuation forum.

Thanks for your help.