No cold water entering the machine (Zanussi WDT 1085) when switched on?

Although water is at correct pressure and is proven to be there at the entry tube to the rear of the machine, water is not getting into the drum. I can hear water dribbling into the front soap dish but in order to carry out a wash I have to physically pour water into the drum. Could this be the failure of a valve or a build up of limescale in the machine cold water entry tube? If this is a valve failure, is it possible to replace the valve? Thank you