It seems silly to say that a castle is old fashioned, of course it is, but it is a bit like being in an old folks home; lots of rose pink velour arm chairs.
Staff were great, the man at reception sorted out a couple of wrinkles for us, and breakfast wait staff were great. The breakfast is good; dining room is small because of the architecture so you need to pre-book a dining time.
Our room, with four-poster, was the most expensive option but was very small, and while some people may say a basin and loo "hidden" in a wardrobe is amusing, others of us would say it's naff. Ditto the bath/shower in a corner of the bedroom, on a raised platform.
Overall, a quirky stay, possibly lots of walking to get to your room but better to stay in the castle than the newer annexe. Approach with a sense of amusement.