Help!

[Simon Hadfield]

Hi, my first post and I could do with some pointers please. My wife and I have a 1965 GMC Surburban, it was the one seen briefly in the film Dark Shadows and we effectively purchased it from the film company here in the UK.
The body was in great condition, that’s restored and painted and and we have rebuilt the frame and running gear (it came over here with Chevy already installed) and now want to fit the body back onto the chassis.
Now, waiting in line for a sales assistant at any of the parts sellers costs a fair bit when you are calling trans Atlantic and the time difference also doesn’t help. I have tried to buy a body to frame mounting kit but I have been spectacularly unsuccessful. Ideally I need all the rubbers and the special bolts and associated hardware. No one seems to be able to help (one operation really struggled to find any enthusiasm at all...) so what do you guys do?
Is it possible to use parts from another model, or year, or even manufacturer? Is there a supplier who is really on the ball about Surburbans as opposed to the pick ups?
As I say it really doesn’t help being this far away, so any hints or recommendations would be super helpful.
As we progress and we get into the details I’m sure I will have more questions, so thank you in advance, I will try and get some photographs of the build up as soon as possible.
Cheers!