overfilling indesit omega 1200 ecosense?

above mc overflowed out of soap tray etc on fill phase at start of cycle. switched off m/c and water inlet stopped so i suspect inlet valves - hot and cold - are working ok.
outlet hoses clear, not kinked, not siphoning.
Conclusion : fill control mechanism is not working. Is it something to do with pressure chamber(s) and pressure switch(es)?
Clues and instructions much appreciated