Freelander 1 Drain the gearbox?

I recently replaced my clutch - successfully. However, in the process I damaged the reverse light switch wiring. I have tested it with a test meter and it shows an open circuit when it's in gear or not. I've a replacement on the way.

My question is: is it possible to replace either of the 2 gearbox switches WITHOUT draining the gearbox?

Are they higher than the filling plug? Worst case some oil comes out and you can refill.

If you have a FL1 the reverse switch can be fitted without draining the oil, 19mm deep socket needed once you have removed the plug wiring, behind drivers side wheel which also needs to be removed.