The answer to the problem is that the thermostat has come out of its clip as previously stated and I'm sure if anyone with this problem checks it out it will be that. I also went through other solutions, and the fault disappeared for a while, unfortunately, in my case me fixing the thermostat was too late, and on my machine it had also blown the heater element (big hole in it) so that needed to be replaced. The no Salt or no Rinse aid cure, I must say I've not come across before, but I could be wrong. Please if you have lights 2 & 4 flashing, UNPLUG IT, and undo the top 6 screws in the door tilt the panel down and put the thermostat back in its clip (down & right of middle on the inner metal plate, 10 mins max) before it blows your heater too. Many thanks to whoever put up the solution first.
Hippytitimus, March 2010