ID did nothing wrong in his physical handling of the situation,
Yes, he clearly did... unless he is claiming to own the seafront and wanted him to 'get orf my land' (which would still leave him in a legally dubious position). The fact that he is a useless bully and ending up on his arse whilst manhandling this elderly man is irrelevant. He had no right whatsoever to physically engage with him.
The old man would have been perfectly within his legal rights to chin the cunt - providing, of course, that he had a sincere and legitimate fear for his personal safety of (copyright Steven Gerard) ... and assuming he could have actually found a chin on the flabby tory cunt.
As for those other fuckin wankers standing round watching this assault on a harmless senior citizen...