Mine had bounced of the striker for ages but it would close reliably if you didn't slam it The car went in for a service and the garage noticed the problem with the door catch and lagged it with a thick grease I picked the car up and the door wouldn't catch at all - had to blitz it with WD40 to free up the mechanism
Yeah I found weekly brake cleaner blast followed by some wd40 worked, but it still opened on bumpy roads.
I think the only option is to find decent second hand ones. I phoned TPS last year to try get a new one to be told they were no longer available. Have seen them listed on Audi Tradition though, but apparently you have to go through a dealer to order anything from them. I just wonder if a good strip down, clean and regrease is what's needed, but they seem to be finickity as to what grease/lubricant is used
