How can I fix my Zanussi F1245W, it won't spin!?

Hi,
We have a Zanussi F 1245 W washing machine that gets to the spin cycle and builds up speed but then cuts out.

The machine has a function that tries to balance the load if it is uneven by reversing the direction of the drum a few times and it seems to be doing this each time.

It never actually spins and eventually gives up leaving the washing wet whether it has a full load a just a few items.

We have checked the pump enclosure and it seems clear. The machine drains OK. There is no water left if we run it empty. It just doesn't spin.

We have two children under 3 so it's mounting up a bit. Any advice would be greatly appreciated!

Thanks in advance