Trust Neil Tennant and Chris Lowe to take the good old fashioned Christmas song and turn it into something that’s extravagant and entirely commonplace at the same time. Trust them to put It Doesn’t Often Snow At Christmas at the end of their set, and trust them to be accompanied, in passing, casual like, by a troupe of dancing Christmas trees. For most bands I’ve seen live, that would be weird any time of year (possible flora exception: British Sea Power); for Pet Shop Boys fans, it’s probably a subdued way to close the evening.