Zanussi Dishwasher overfilling with water

I have an intermitent problem with my dishwasher over filling with water. Instead of an inch of water it just keeps filling up until it leaks out the front. If I put it back to the start of the cycle it will empty out. If I switch it to an alternative cycle, and then it will work again for a while. When it does it again I switch back to the other cycle for a bit. What could cause A. the overfilling, and B. the problem to be intermitent. Thanks

Partial blockage, some debris moving around causing a blockage, faulty pressure tube or a faulty pressure switch.

Machine stopped mid cycle last night, timer knob stopped turning, when I advanced it slightly it made wirring noises, but did not turn. Could this be the source of the problem?

Nope. This is another problem. Depends on where it stops, could be lack of heat, could be faulty programmer.