okay pid autotune total failure.
once it hits 20c past the set temp (tried several) it just says: temp too high, PiD failed.
So I think my next move is to try and flash it back to the factory original firmware.

That way if I still have the same issues - looks like I need a new board.
Which for around £30 Isn't a big issue.
Just a 2-3 week wait.