If it was for real, PIATs should be useful against nothing. There is no recording in all WW2 history of a piat actually knocking off a vehicle. Yes, it was THAT bad.
Mate that is bullshit, of course PIATS worked, they wouldnt use them if they didnt. You can find plenty of photo evidence and records of PIATS being used. Jeremy Clarkson's father in law won a VC at Arnhem for knocking out a tank with one.
https://en.wikipedia.org/wiki/Robert_Henry_Cain#Battle_of_Arnhem