Help please...

I very much enjoyed reading this mystery novel recently - the Stately Home Murder by Catherine Aird. It's the third novel in her main series, slightly older fashioned style mystery similar to Agatha Christie but very enjoyable!
Anyway help please - can someone - anyone - identify which stately home or possibly palace or manor house is actually illustrated on the front cover? I think I've been there but since I spent most of my life in the UK touring places like this - I am struggling to remember! The book just says the photo is taken from "Britain on view" and a four page search of google images didn't find help me find a match!
Help please.... Where is it?