I rang Suncamper this morning and good news!!  I don't need a new circuit board because there are separate fuses for each switch behind the front panel of the control board.  I levered the front of the board off as instructed, and there were all the fuses.  I pulled the offending fuse out and replaced it with one of the spares I carry, and all lights and switches are now working again.

I am surprised that the auto electrician didn't know where the fuses were, but I'm happy that I avoided spending money unnecessarily.

I will definitely set off again tomorrow morning.  I think I will catch up on my washing and then it will be another lazy day trying to avoid the heat. The forecast for today is an expected top of 36 degrees.  Phew!!  I've had this heat.