Cambridge and Manchester seem to be the biggest mistakes made in that table.
I would debate about where Oxford / Warwick / Imperial stand in relation to another for maths as much as the next person. Nonetheless, I don't see how Imperial or Warwick could possibly have a score higher than Cambridge for mathematics.
Keep in mind, last year the Guardian said St. Andrews was the best university for mathematics in the UK, this year it would seem St. Andrews is 5th. I'll probably be at Warwick next year, so yeah I'd take 2nd place, but I wouldn't take it seriously given the state of that table.