Washing machine not spinning

Good evening, I have a Siemens Extraklasse XL 1400 which is about ten years old. For most of its life it has been connected to a supply of softened water so the internals should be clean. We moved around six months ago and since then it has been on a normal but hard water supply. The machine is used on average three/four times a week.
This evening it has stopped the spin cycle as part of the wash program. The washing cycle is ok but no spin. Even setting the control switch to the spin only cycle produces nothing. One can hear the relays or solenoids clicking inside but the drum does not rotate at any speed when required to spin.
Have checked the impeller under the cover at the bottom right of the front and it is clear of any debris or items of clothing (socks etc).Any ideas please? Many thanks Chris.