Clio II central locking won't work and won't start.

Hi. Our 2001 1.2 Clio has what I think is an immobiliser fault. The central locking won't work, currently unlocked. Tried both keys with new batteries. Engine won't start either, the immobiliser light doesn't come on at all. The vehicle battery is fine. If I link 12v to the starter the engine turns over but won't run. All fuses ok in both boxes. Headlights work, fan and radio work. Elec windows, indicators, wipers and hazard lights don't work.
I've looked for the I/R receiver which two people told me would be by the interior light / rear view mirror but it's not. I have no idea where it receives the signal from the key?
If anyone can point me in the right direction I'd be very grateful. Its for my daughter to learn on and she's very upset that it won't even start now!
Thanks.
Mark

Clio II central locking won't work and won't start.