Since switching off and back on at the socket, has the code reappeared?
OK, thanks for that.
F01 is a motor triac fault.
The triac is on the main control board.
Does the door lock light come on?
Sorry, it sounds like the main control board is your fault.
Try closing the door a little harder than normal to see if it locks.
If not, unplug the appliance and take the rear panel off.
The main board is bottom left when viewed from the rear.
Take the board out.
Check the wiring and plugs to it.
Check the board itself for any damage.
If all is ok, it's likely you'll need to replace the board and have it programmed to your appliance.
Check it out, see what you find, let me know.
You can a refurbished one already programmed or your own one repaired.
They do a lot of work on the electronics for these machines.
If you send them your old board, they test it, repair it and also tell you if anything else may need changing.
The alternative is to have Hotpoint do the repair on their fixed price, parts and labour, repair scheme.
You need to call them for their latest prices and schemes. ( I think they start at £108).
Hope this is of some help
Let me know how it goes or if you need more help