I was pulling out of a parking space at a local supermarket yesterday, put the car into reverse and found I was still going forward. The shift was very light so I realised that something had become disconnected. I managed to get home without needing reverse and was about to pull the shifter apart when I thought to myself - I am sure someone else has had this problem, let's Google it first ... low and behold I came across this post.
I climbed under the car first thing this morning and sure enough the plastic cap had broken off the linkage. Phoned my local Porsche dealer and lucky for me they had one in stock. It was bit fiddly and I struggled to get the new plastic cap on the ball joint but managed in the end. Car fixed again
Many thanks to boxster7614 for taking the time to publish this post. Without it I would have spent many more hours pulling the shifter apart before I checked the back of the car. The diagram was also really useful as I was able to point the spares chappie directly at the part I needed.