thanks Bonus, that's exactly what I needed to know.
My goal is to pretty much replicate the white van at the start of this thread, down to the wheels which I think are 15" Compomotive ML's.
I'd planned to fit the arches, then measure from there back to the current hubs to see what size is possible.
I'm not certain what the diff is that's in it at the moment, haven't got that far.
I don't think it is anything special, the previous owner suggested it might be a 2L Mk2 diff, as it has mounts for a sway bar. Looking at it though I thought it was less beefy than what is in my 4 door.
Will suss that out further.
I'll cut the wheel tub as suggested at the join, and pattern up an infill.
I recieved my panel delivery came yesterday, sills,floorpan and heater bubble. I expected they would need some tweking to fit, but did not expect they would be so rough. The floor pan had ripples in it where the stamping should have been flat, it looked like I made it. The heater bubble had been manually panel beated to get some dents out, and still needs work. And they were not painted like you see online, just left bare metal.
Overall, if thats the quality of M*gnum Panels, im not too excited.