Thanks, I was quite supposed he hasn't rushed in he has a good selection of info like you mentioned, and has rang every Lawnmower shop in the uk looking for a 30's Dennis mower carb as the same one was fitted, we very nearly bought a complete mower but the bloke didn't come back with a close up photo so it wasn't worth the risk, we even have a guide book on it which is excellent. The Gear box is unbranded we suspect made for Enfield, doesn't look like a Burman or Albion though, we have two both in bits so hoping we have enough to make one good one, we do have an end plate from another box that's marked Enfield but its different.
He has found the correct Lucas Magdyno thing but its £300 and has the typical weak spark, just waiting for the rest of the parts to arrive and he will build a basic electronic ignition until he can find a cheaper mag.
I think the next task whilst looking is to make a cover plate for the tank as it has a hole through it for the light switch and ammeter, it will put his sheet metal work skills to the test and teach him about different hammers.