Hi Aled, the code you have appears to be a jammed pressure switch. Either it's blocked faulty or the module has failed.
Pull the plug and remove the top of the machine, take a look inside towards the rear of the machine.you're looking for a cylinder type device with wires on one end and a small bore pipe on the other.
This pipe runs from the pressure switch down the inside of the machine and joins onto the tub( outer drum ), it's purpose is to detect the amount of water inside the drum, often the small pipe gets blocked up, adding too much detergent can cause a blockage.
Pull this pipe off the pressure switch and blow down it, it needs to be free of any blockage.You may hear a click from the pressure switch when you remove the pipe, that's a good sign and means the switch has closed and the pipe is blocked.
Most pressure switches are of the cylinder type about four inches long but yours could resemble a disc type, same thing wires on one end and the pipe on the other.
Now the module that Tony describes actually controls the presure switch so in theory it's a fault with either or it could be a loose wiring connector.
Once you have identified both parts then I think you will find the part numbers on them.
Indesit/ hotpoint do a five year warranty so if you can prove to them that you machine is less than five years old, they will fix it under the fixed price scheme ,
Hope you get it sorted I know what it's like when you can't do any washing. Hope I have helped somewhat and good luck :)
paul
October 2012