When I saw the prompt I knew the place, so we visited two days ago. I’m pretty sure it’s the same place. From the front you can’t see the size of the hall. You walk over the bridge over the moat. Through an archway into the courtyard.

Inside the house is dark and panelled in old oak. There are places where wall paintings are being restored and the old windows are fantastic. Up and down many stairs and spiral staircases you reach the long gallery. Beware the bees nesting at the bottom of the stairs though!
Then outside to the knot garden and main garden. These are hidden round the back.
All in all not Monochrome at all. And if you want to know where it is you will have to wait for Sue’s explanation. I won’t spoil the mystery (and I might not be right!)

