I need help with a project I have bought which I was going to use for spares but after giving it a look over I think it might have a bit of history to it.My thoughts are that it has been built rather well,its frame has been modified with twin rails under the motor (the frame number is d10***)and is clearly bantam and the rest of the bike has been built with a lot of thought,does this ring any bells with anybody.Thank you.

In your opinion which parts have "been done rather well"?

I think just the set up of the bike back in the day of course it’s not like the modern nearly bantams but maybe a forerunner,I would just like to know who built it.