The drill+WD40 method worked miracles on my 06 Altea.
Intermittently it wasn’t opening from the outside using the fob and the
problem kept wandering. Last time it the front right and the rear left door acting up. Took the front right door panel off, the old WD40 took it’s time to work. After about 15 minutes the door worked fine, even the rear left one without touching it! We had to put the champagne back on ice, because now the front right wouldn’t open from the outside. With a moderate amount of bitterness I’ve decided to call it a day. This morning all doors work fine and open from the outside, and hopefully it will stay this way. Onwards and upwards on the snag list.