Hi Dave,
Great to have you back in fold again!
I think I know what your issues are with the mounts.
There are two sizes available, on ever so slightly smaller version for the Herald anti roll bar (with smaller rubbers too) and then both the larger rubbers and mounts for the spitfire ones. I actually had to file open the mounting holes to get the new mounts to fit - BUT, with the correct rubbers and metal mounts there was no deformation whatsoever.
The wrong parts possibly?
Trevor.
http://www.sammiospyder.blogspot.com/