Am I the only one to wonder whether it is raze or rase? They are alternate spellings of the same synonym for fell and both sound like rays. Unusually ambiguous clue from the usually precise Paul McKenna ...
They are equally good answers, but 'rase' is listed in Chambers under the headword 'raze', and a google search for 'razed to the ground' and 'rased to the ground' serves to confirm that 'raze' is the more common spelling. Not an egg-ceptional clue, though...