Ludlow Castle. 
Open Sat-Sun in February, Ludlow, Shropshire.

Spend a night in a castle! Explore the fascinating medieval ruins of Ludlow Castle and step back in time to catch a glimpse of the lives of kings, queens, princes, judges and the nobility. And then relax in your own luxury self-catering accommodation. The castle is open to day visitors too, of course. Read on here: http://www.ludlowcastle.com