Thank you for your input MM.
You have no idea about my qualifications so kindly keep your opinions to yourself (and yes, I had already checked the water level meter, and yes the water heater was turning on)
I  finally tracked down the fault. I went back to the wiring between the CPU and inlet solenoids. Continuity was fine. SO I got a pin and teased out the contacts in the plastic connector housings. They're very fine so it needs a light touch. I reconnected everything and the machine sprang back into life.
Even taking into account the cost of parts  I saved myself a small fortune in repair bills, as I live in France where such services are very expensive indeed.
                
 Tom
                
 November 2013