Could do a lot worse than Sussex by the sea, a fine anthem, that sums up everything good about England, but Sussex in particular.
Having given the matter considerable thought, I suggest this: We should keep the "Who's on Top of the Pops?" intro too as it will mostly be used when presenting sports persons with gold medals/world cups.
A classic though it does have alien religious overtones. This has just come on random play and if you listen to the lyrics, it fits pretty well: