It's quite a few years since friends dragged me, somewhat unwillingly, to join them at Summerfields Holiday Park (Scratby, Norfolk), over Christmas, but I enjoyed it far more than I thought I would.
I've just checked their website, which confirms that:
(a) they're open over Christmas this year (from 20/12 to 27/12, with 3, 4 and 6 night breaks on offer); and
(b) they accept dogs (in selected chalets, at �30 per dog).
Possibly worth an enquiry?
http://www.richardsonsholidayvillages.co.uk/su mmerfields/page/home.html
Chris