Hi  It makes sense for any Douglas owner to become a member of the LDMCC. You will receive an excellent magazine every two months with free advertising for your needs or items for sale, have access to spares, technical advice, and contact with over 1100 members with similar interests. The cost is currently only £12.00 a year. To reach their web site with application form for membership, go to
http://www.douglasmotorcycles.co.uk/ Further thoughts on your bike; If it is a CW model, it should have a three speed gearbox and flywheel clutch also chain final drive.
The thought passed through my mind that if the frame prefix was in fact a 6 rather than a G or C then it is more likely to be a TS model which was clutchless and had belt final drive. There should be a minimalist chain guard comprising little more than a semi circular section guard about 1" wide covering the top run of the chain and the back of the gearbox sprocket. Â Chris.