Better to use the time machine to go back and conk the guy destroying the tapes over the head, then take the tapes back to the future.
People always talk about using a time machine to kill Hitler, but I think that saving the lost Doctor Who episodes should be the first thing a time traveler does. Its a nice, simple thing to do that will (probably) not break history. But, with my luck the destruction of the DW episodes is a fixed point in time
