Thanks everybody. the footage is over 100 years old so the loss of quality would be *I think * unnoticeable, and the frame would always have to be adjusted or sit 4.3 inside 16.9 with a frame anyway.
We have access to the original film reel but no money to digitise .
We'll give the red giant plugin and 3D warp a bash and see how it turns out.
Thanks a million for the advice! I'll check back in when we've found a workable solution!
Thanks :)