I just had the same problem with a Hotpoint 7810 plus , its been going strong for 20 years and its seems a shame to replace with a machine designed with 3-5 year obselesence. In my case the drain pump was blocked with small fragments of what looked like plastic but could have been limescale. Tools needed:-8mm Socket and nut runner(socket-screwdriver adapter) . Ensure machine is empty but some water will be still in the salt dispenser so lay down towels/heavy blankets. Turn machine over onto front face, rotate through 90deg to place on its side, remove the base front panel 2 small pk screws gets access to drain pump area, unclip drain hose and pull off pipe from drain pump, unscrew 2 mounting screws holding drainpump , pull drain pump off of base unit, remove earth and two other power connectors (make a note of what connections go where. check to see if impellor can rotate or for obvious blockages. You can get a replacement drain pump for about £25-35 if it not a simple case of unblocking.
Roy Duggan, March 2008