Hi @aedwards1982
Here's the [document|27646|tech sheet] for the washer that will help.
On p.7 it gives the possible causes for a F8 E1 error code.
It details how to test the water inlet valves on p.13 ''Test #2: valves''
If it is determined that the cold water inlet valve is faulty the part number is ''W11168740''. Search online using the ''part number only'', to find suppliers that suit you best.