I heard Alan say it had been a "few Hz" out which indeed it was (648.003), giving a bit of a "wobble at night in fringe areas. He said it was now a few hundredths of a Hz out with improved nightime reception.
Easy enough to check the facts and not speculate:- http://websdr.ewi.utwente.nl:8901/?tune=648amsync

Not bad for a free running crystal.