The dreaded parking sensor...have searched

Havent posted very much on here as basically the car has never had any faults:thumbup:......till now as the parking sensors have packed up. Using the search on here i have done the listening test and found 3 that are not clicking:thumbdwn:...No wonder the system doesnt work, all on the rear from the left rear across as the right rear is clicking. The question is though, will the sensors from across the VAG range fit as i have found a few on the ebay that look very similar from an audi A5 and a VW and means I wont have to shell out the daft amount of cash to the dealer...any answers welcome to clear this up, ta:D