How do I get to and open up the pump for my Hotpoint Wf860?

Washing machine cycle gets so far then makes a really load whirring noise and the water will not drain out. A few months ago when it was in warranty the same thing happened it came up with f0-5 and the engineer came out and removed half an underwire from the pump. It has subsequently happened again (probably the other half of the underwire). I can get to the pump if I open up the back but I can't seem to remove the rachet plastic clips and don't know how to get into the pump. It literally took the engineer 2 minutes to fix the last time but for the sake of over £80 just for him to do it again I would like to try it myself. I did remove the big plastic drainage bit where the plastic balls lies and found 50p which I removed but it didn't make any difference.

Can anybody help?