And the bank is saying that a) they can't say who did it because of the Data Protection Act, and b) they can't stop it happening.
Hang on, this is a direct debit? Per the Direct Debit guarantee, "If an error is made by the organisation or your bank or building society, you are guaranteed a full and immediate refund from your branch of the amount paid" and "You can cancel a Direct Debit at any time by contacting your bank or building society."
So where's the problem? Either the bank is honouring the guarantee, in which case they can stop it (and fully refund Clarkson), or they're not, in which case the bank is in Really Deep Shit. And IIRC crimininal investigations trump the Data Protection Act, so the bank can (and should) reveal who set this up.