Thank you Brent Good suggestions and i will check/clarify once engine and gearbox are out. Last hours i tried to find the dislodged spring without disassambling the engine
I unscrewed the 12 bolts of the pressureplate to push it backwards and have a look in front of the pressureplate. Sadly there is no way to push the pressureplate more than 5 mm back. Not enough space to put in a endoscope-camera (is it that all endoscope-cameras are as junk as mine is???). Not enough space to take out the spring (if i would have found it). However - my "A"-season is over here and i will take out the engine next (asap) . Thank you again Brent