Hi Andy,
the only time I have had to deal with warped resin was on a 1/32 scale Pitts stunt plane, a few years ago.
I had to put the wings in really hot water and twist them back into shape (wearing thick rubber gloves)
This did work and the aircraft is still straight. I was worried about it reverting to default but apparently this does not happen - the bottom wings are still attached to the top ones after 5+ years!
The resin in my kit was grey though and may be different stuff.
From what I can gather, this hot water method is pretty much the only method for fixing warped resin.
Hope it goes well for you, I will be watching your thread.
Regards,
Steve.