The website is now listing the 2022 schedule and there are currently eight 4-day adventure vacations available to book. And the list of DMs is pretty impressive.
Never played an organised game in a castle, but remember playing two summer night games in the 6th form at Thurnham Castle and Coldrum Long Barrow, both near my home.
The one at Coldrum featured undead wights in, you guessed it, a barrow mound, and was pretty spooky.