I've had a great day on it today where everything has just gone right, heres a pic of the simplest frame jig in the world, I chopped the front frame off the doner bike but it was too straight so I lined it up with a bit of card and drew on the where the frame needed to go an it worked a treat. I then filled the frame with sand to stop it kinking, heated it up and bent it so it lined up with the original--simples.
I then made a couple of spacers fit the back engine mount, chopped the end of the original 1932 bracket and welded it onto the CG front tube, and used a bit of 2.5mm steel for the top bracket, and thats the engine fitted and the sprockets line up lovely.
By using the back of the original frame I've still got the exhaust hanger and also retained the center stand ( I've now got three working stands
front, middle and rear !) and the rear brake peddle which saves a load of hassle, I just need a longer brake and torque arm an I've got back brakes, but somehow I dont think that bits going to be as easy as fitting the engine...