I've not seen it, but part of it was Filmed at Gwyrch Castle in Abergele. I had a wander around there last year (with permission, it's being transformed into a 5* hotel), and they mentioned it being filmed there when we asked what the straw lying around parts of it were for.
I'll see if I can borrow a copy off a mate who seemingly has every movie ever made, and have a watch of it.
Searching for the ever elusive Underground Titty Bar.
DDDWH CC