@glennarthur looks like the Jetta 5 and Golf 5 share this. For now, all I have to offer is the Transmission repair part from the workshop manual [document|31803] Page 92 is talking about the Selector mechanism, The images in the manual are not the greatest but hopefully help a bit.
Definitely some interesting reading. Take a look at page 118. Did they really make it this complicated? Shift Lock Solenoid? Selector Lever Park Position Lock Switch?
If this is from the Roo, it has to be from the bottom, which corresponds with what the manual shows. Sorry, nothing seems to ever be easy. Kraut Engineering at its finest.
Check the fuses in the fuse panel on the inside instrument panel. Fuse #2 and fuse #14 (-Selector Lever Sensor System Control Module) #SC30 Transmission Control Module (TCM) -Direct Shift Gearbox (DSG) Mechatronic
Furthermore check the transmission control module (harness and all) its in the front left wheel housing.