Thank you Leon for this thread. I will read it thoroughly but later, there is so much information, I need to read it near the bike !
Steve
So sounds like my mistake is going to end up in a more correct bike, although there is a LOT left here.
Can't tell for sure from pictures but is it a Douglas blue tank?
So frame made in 37, but how can one tell if it was or not a "Pride & Clarke" bike? Maybe the reply is in Leon's link...
I am addding below the information you sent me by message for ease of later access
The frame 6P 404 is from a 1937 Aero roughly half way through the production run.
The engine 6/L 178 is an early 1936 unit the number shows that this engine was No 77 off the production line for the 6/L type.
The gearbox 6Q/237 is a 1935 foot change gearbox. Albeit it has had the foot change option removed and replaced with the hand change casing
During 1937 Douglas motors made the foot change option available as an optional extra, see the pics of the extracts.