I checked through a variety of possible causes - draining, slipping belt, poor motor connections.Apparently high mileage machines can do the "Click Around" when the motor brushes are worn too short and or making poor contact but mine were OK and cleaning the commutator made no lasting difference.
When I asked a local appliance repairer he said that this common problem probably accounts for the high number of recent Indesits in the scrapyard.
You can try (after switching off the machine) locating the main control board which is in a long slim plastic case in the bottom left corner of the machine when you have removed the back panel. Make sure that there is still no power connected and undo the circuit board edge connectors and remove it from its horrible casing with its crappy clips. Avoid touching components on the board and spray WD40 or circuit board cleaner on both sides. Reassemble.
WAIT UNTIL THE BOARD IS COMPLETELY DRY BEFORE SWITCHING ON THE POWER.
This really should not have much effect but it is what some repairers will do to get an extra 6 months out of the machine.
This is the longest lasting (about two months so far) fix that I have found.
Good luck
Rick
April 2006