He has slated F1 on many occasions for being boring, so I don't think he's actually that bothered about it. I'm sure if he got a bells & whistles invite to Silverstone he'd attend! He did do a feature on one of his old programs in the mid 90's about Monaco and interveiwed quite a few F1 drivers, but he probably realises the ratings attraction of that, and we all know who contradictary he can be when he wants!
Richard Hammond prefers Nascar, Clarkson seems to like (gives the impression) that he prefers F1 and I think Captain Slow likes neither sport..
Realised pumping hard earned cash into a team who do not even use a wind tunnel is a complete waste of time.