Bubby - that depends on your budget.
New pans, frames, and backs are available but prepare to spend some serious money.
Used but mint parts are also out there, again for serious coin.
Like Terry said, if you search you can find parts that will work.
I bought a MK1 Midget parts car in large part because it had restore-able seat parts. Parts car = $500. Sold $350 of it's parts = seat bits and good pair of SU's (and whatever else I need) for $150. (until I sell a couple more bits then I should pass over from the red side of the ledger to the black side) :wink: