Lack of power, noisy fuel pump and dodgy tickover sound like maybe the fuel filter's blocked
Don't waste £15 on a new one though (it might not even be the problem) -
nice and simple fix:-
whip off the fuel filter & work out the direction of flow (there's an arrow

)
Blow quite down the filter in the opposite direction to fuel flow - all the debris that's been filtered will spray out of the filter and it'll be ready for refitting

You'll probably get a nasty petrol taste in your mouth but £15 buys loads of chewing gum
