[Mike the mechanic]

Hi, once you remove the trim plate/ring, you need to remove the two bolts that hold the switch to the dash. These bolts are anti-tamper bolts so you will need a little punch or chisel and a little hammer to tap the bolts loose. Once those are off, reach under and pull off the round connector/plug. There is one more bolt left that holds the long part of the switch to the steering column. T gain access to this bolt, you must remove the lower dash trim. the last bolt points downwards and is a hex head (I think 5mm) but is locked in place by a 13mm nut. Loosen the nut and then the bolt. the switch assembly should just slide out.
Hope this helps.

Mike
86 Carrera (soon tt)