240 General: Door trim adhesive

[Clifford Pope]

I mean the flat panels along the bottom.

These seem to last for years, then suddenly begin to buckle and peel off at one end.
On a previous car, after a failed attempt to glue them back, I found some new old stock, carefully preserved in a pack with wooden padding to keep them flat. I used the recommended double-sided trim adhesive stuff, and they looked wonderful for half an hour. Then they started to curl up at the ends.
Meanwhile, the old ones, laid flat on a shelf, had returned to their proper shape, and looked now in perfect condition.

One on my present car has just started to curl away at one end, so I'm back in the old game of trying to fix it flat.

Any observations, experience, advice here please?
Last time round I ended up using black self-tapping screws and large washers.