So now, I am also the proud owner of a James ML.
it is in good condition, has been injected into oil for the last 40-50 years.
Almost complete, except the center stand and unfortunately all the miliary parts, such as, tool box, foot rests, handelbar-quick release, and front and rear lights ..
so if anyone has these parts for sale, I am the buyer for them.
You should use a Villiers 'Hammer-tight Spanner' to remove the flywheel, but failing that a good stout ring spanner will do. The centre nut is captive within the brass flywheel, so hold the flywheel still and give the ring spanner a couple of smart whacks with a hammer. Once the nut starts to move, keep undoing it and as you do the flange on the nut will draw the flywheel off and it will become loser and loser until it can be taken off. The nut should be turned in an anti-clockwise direction and after a couple of turns will start to feel like it is tightening up again, but keep going and it will come off eventually.