From the sound of the fault, its failing to drain, which in turn is stopping it from spinning.
Are any error codes shown on the display, this may help confirm if its a pump, sensor or other fault.
In terms of DIY, I would suggest you start with checking the filter, this is described on page 13 of the manual. Turn the machine off at the mains, remove the kick plate on the bottom right of the washer, use a cloth to soak up any water, and a cup and bucket to capture water which comes out as your slowly turn the cap anti clockwise, with the cap removed use your finger to clear any debris you can see, you should also be able to move the pump to prove it hasnt got stuck, then place the cap back turning clockwise.
Run the machine and see if that clears the fault, if it doesnt, pull the machine out and check the waste water pipe. Remove the pipe from drain pipe and feel the pipe in your hand, if its heavy and cant be easily compressed with your fingers its holding water and you need to rod it to clear the blockage.
If neither of these issues clear the fault its most likely to be a pump or sensor fault, the average price for a pump is £30, you can pick up one here, then you looking at around £50 to have someone come out and replace it. However an engineer will strip the machine down find the fault and replace the part for around £50 labour.
Please let me know how you get on, and if you need anything clarified.