brianconwy said:

I ordered this switch which is for a defender/discovery 1 as someone somewhere said it was longer. it didn't look any different from the one I took out but has worked well while the car was running.

https://www.ebay.co.uk/itm/Land-Rover-Defender-Discovery-1-Reverse-Light-Switch-R380-CDU51L/220376877329?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Click to expand...

Would be good to know if it is really longer or in your case the problem maybe was different? In my case I surely needed this 3-4mm extra lenght as even I removed the washer from the new sensor it was too short.
As it is cheap I will order one next time just to have it as spare and will compare to the original one.