I got a few moments today to document this for you Chris.
When the switch unit is actually removed, you can see that the switch operates on a pivot as shown here:
So to get it out, you need to place a slim blade (we use one of >>these<<
) down the side of the switch button, at each side, to dislocate the pegs from the holders:
Having removed the switch button, there is one T15 torx screw to undo here:
The switch unit then slides out for access to the end of the cable and the switch.
The hard part is knowing exactly where to place your blade at each side, which is why I showed you a switch unit removed, but re-assembled with the button in place. You need to be careful doing the first bit as the plastic may crack while you are manipulating it.
Hope that helps.