M and S issue

I've replaced the XYZ switch a few years ago, but now getting M&S lights flashing, and D in LCD flashing - but not going into limp and starts fine. Mainly happens when I've shifted (slowly) from R to D. It is a P0705 fault.

I had extended the AC drain tube previously but saw today that has failed and water is dripping onto the wiring loom next to the switch. Plan to sort out the drain hose issue tomorrow - but does this sound like the switch itself may need replacing/refurbing or could the water be the issue? Or perhaps chafing in the loom? Will check for that tomorrow too.

Here is the tube we had fitted in the drain hole previously, which is now leaking. Second photo shows the water sitting on the loom wiring..