Some hotpoint, indesit and ariston filters are located in the big black sump hose (the one that leaves the bottom of the outer drum and connects to the pump). Remove the back cover, locate hose, remove the tensioner clip by squeezing the tabs together, remove the hose, take out filter and clean.
Check out my site for info: www.2ndwave.co.uk/manual.html
washerman, March 2008