I don't know what the fuss is about, every second person seems to wear some form of military surplus. Building workers all seem to have a piece of desert DPM. It's hardly illegal if it's sold off officially.
Interestingly if it was Irish military issue, he would be arrested and charged. Because there actually is a law against wearing current issue gear here. It was in place to stop the IRA from poncing around looking as if they were a real army. So ironically the IRA often wore British gear
Which wasn't illegal.