If you want me to direct you to get a better Cradle..... There is a guy in Dunnville, Ontario, that may have what you need. P.M. me. He has a lot of used Norton parts.
To get that spindle out I would go to S.P. Simpson or A. Grainger and get a piece of 2 ft or more 1/2" threaded rod in national fine, with nuts and heavy washers. You need a to make a heavy slide Hammer! (if you can find it locally then that's great). National Fine or Imperial Thread Pitch is getting harder to find in these days and ages). Try Crappy Tire or Princess Auto but don't hold yer breath.
Screw the threaded rod into the spindle on the right hand side of the frame, and your slide weight though the rod and in between the washer and nut at the other end. Wack the f#k* out of it until it walks out of the two bronze bushes and the centre distance piece of the cradle assembly. It's kind of brute force and ignorance as the D.P.O. looks like he used grease as apposed to a thick oil....(140wt oil I use) to lube the (oil-lite) or oil impregnated bronze bushes.
That should do it.
Let us know your results.
Tom