Posh Bosch SMS 6012 GB - timer stopping - Water Valve?

Our Bosch machine kept stopping for no apparent reason then completing when the timer was helped. First stop just before opening detregent carrier. It has now stopped and smells hot. On inspection and front panel removal it seems that it is not allowing water in, its just running dry, no water inlet noise either (its on the mains so its normally audible ) - which would account for a pause in the cycle and the hot smell :-) Is the valve the likely culprit? Is the rinse cycle heated (I could use that as a safer test). Timer is £200, water valve £60. New nice BEKO £218. Machine is 15 years old.