Zanussi ZWD washer dryer not draining properly?

My Zanussi ZWD washer dryer does not drain properly.
Ive cleaned out the drain filter at the bottom right front of the machine,found a small amount of lint.I can see the pump running through the hope when i tested it,so im guessing thats working.I checked the drain pipe from the back of the machine to the ubend under the sink and that was ok.
Any ideas what else i could check please?