If you have the wash light and the start light flashing then this is a control board fault.
Ignore the lights on the left hand side which is the salt rinse aid and start lights as they are not part of the error codeing. Its only the lights on the far right thats the error code.
So if its the wash and start light then its nearly always down to a faulty control board in the base.
Im taking it you have removed the plug from the socket and waiting 20 mins and then plug back in and see if this clears it?
If that doesnt work then remove the plastic cover at the front at the very bottom below the door and there you will see the control board. Check all the wiring is pushed on there tight.
If thats all ok then the control board itself will be the fault and would need to be replaced and programmed. Now if you buy a new one yourself they are sold blank so need to be programmed up. So to do this you will need to also buy the programming kit as well.
Now to do all this it will be cheaper to buy a brand new dishwasher as all the parts to do this will be over £250.
But Hotpoint do a fixed price repair for £110 all in. They will call out replace the control board and program it with there laptop from there for that price.
Sorry its not good news but if you need anymore info just get back to me.