What's an old GTV like that worth, £1500-2000? Crashing it would cost considerably less than filming it. Whilst it's a bit sad to see a GTV getting crunched, far more are lost every day due to broken cam belts.
I don't remember Top Gear crashing an XFR, but if they did you can be sure they didn't stroll into a Jaguar dealer with a cheque book. It would have been an unwanted prototype one waiting the scrap man, almost definitely free of charge from Jaguar's media department, failing that one that's been written off which they'll pack full of filler and slap a bit of paint on so it looks good for its 10 seconds of fame.