"Reasons to be Cheerful" would be excellent, but would need an update to remove the Americana and European references.

"Land of Dope and Tory" and Jerusalem are stirring, which I think is what you need in a national anthem; think of "The Marseillaise" - originally specifically titled as a war-song it's very blood-thirsty,( War song for the army of the Rhine), but England doesnt do stirring we do fawning.

GSTQ always conjures up the very rude playground joke and the Pistols.