Welcome! Grounding issues may best be found by a dealer since they see Patriots all the time and may know where to start looking. In my case it was a bad spot in the harness directly below the battery. Clearly visible.
A few of your symptoms might give others on this site a clue to help you.
Welcome!!! If you're able(and if British automotive law allows), maybe you could eventually import an American-style front bumper to help it stand out? Plenty of other modifications to do as well, if you happen to be interested.