Can't get exmoor refit kit to fit on 1985 110

I've hit quite a snag in refitting my driver's seat with the exmoor leather seat kit. The seat base fit went just fine -- no problems there.

When I try to attach the padding to the seat back, however, things don't appear to fit. My seat tubing is just shaped a bit differently than what I see in the installation videos (a bit more curved) and the back is a solid sheet of metal, not webbing.

The distance from the rear tubing to the from is 115mm, and the depth of the channel in the padding is around 100mm, so the foam will not reach to the back of the seat.

What can I do? I could cut deeper into the foam, I suppose, but I supect that will cause some premature failures in a short time.

Thanks -- I'm in a bit of a bind here, as this is my daily driver...

-Evan-

been here done this. gave up and took the seats to an auto upholstry shop. Guy said it took three people ie 6 hands to wrestle the leather on and hook it @ the bottom. I did this on an 83 and an 85.