Right, done this now on both front doors.
Before, not massively noticeable but once you see it.....and it will only get worse as water continues to get in. You can feel the difference, the side near the door pillar is at least 5mm proud whereas the hinge side of the trim is flush with the door:
Trim after unscrewing, full of dirt. Seems to have come apart quite a lot more than you would think looking at it while attached to the car. This seems to be because there's a recess behind where the trim fits on the door so you only see the distortion on the fascia, not on the backing.
I cleaned out all the crap best I could using a small flathead screwdriver, a nail and a stanley knife. All of the rusted metal came out. Then used some cotton buds to clean the inside surfaces.
Clean:
Biggest problem I had was deciding what glue to use. There seems to be two ways to glue it back together. Where the trim has come apart at the very top, it requires a lot of force to close the gap and even then it's impossible to completely get it back to how it was. I'm not sure it's even necessary to completely close this gap as the recess in the door will allow it. If you clamp the trim as below, it will straighten the trim but the top gap remains, the point of contact is further inside the trim. I considering using one of them super glue with powders like QBond or supafix AP4, I think they'd work best if you left the gap at the top, as there's virtually no working time with them you'd have to clamp up, then fill the gap with powder and glue:
I decided instead to completely close the gap at the top, so that mean putting all the pressure at the very top edge of the trim. Had to make a jig for the clamps using some 2x1" timber and a 7x7mm piece of steel(b&q), the steel fits perfectly in the recess at the top edge of the trim:
All masked up, dry run before gluing. Trim virtually back to where it was, just 1mm or so off laying flush. Requires a lot of pressure to close this gap so glue needs to be strong.
Opened up the gap again, filled with glue, clamped, cleaned off, removed tape. I decided to use Stixall(clear), it's similar to tiger seal, sikaflex. I know how strong it is, allows more working time, easier to wipe off excess/spills and is also a sealant. Only downside is it takes 24hours to fully cure so I had a day or two driving around with no door trims on:
Clamps removed:
I also noticed on one of my trims, a little section of the underside had come apart swell, I just sealed this up:
Done, don't notice it at all now. It's not 100% perfect, the plastic and steel backing have obviously been distorted for a very long time and as such you'll never get them 100% true again, as well as that the metal backing of the plastic is no longer there.... but it's 99% and you'd never notice it.
) causing them to corrode and bulge.