Scenic electronic fault

I left my 1989 scenic unused for a week and retuned to find that neither of my keys would activate the door lock, or turn of the immobiliser. The next day however everything worked and I used the car as normal. The next day the keys failed to work again. No immobiliser warning light appears, neither on, nor flashing and the electronic. I took the sensor out to ensure that it was clean and dry (suspected cause of fault) but it made no difference and I discovered that the lights and wipers do not work, nor hazards. Interior brake and other dash warning lights seem normal. A local auto electrics man put his meter over it, discovered nothing and went away to think about it and has not been contactable since. The under bonnet stuff does not match any illustrations I can find. HELP!!!

Scenic electronic fault