The Thirteenth Reunion
Finally, the location of the large white stately home has been solved thanks to Bob Rocca who contacted me as well as
Tony at Avengerland.
The house used is Warfield Hall, Warfield near Bracknell in Berkshire. The house is now privately owned so unfortunately there is no way
of getting a photo of the actual house but Bob has kindly provided this photo of the entrance.
The same house was used in 'The Professionals' episode 'Wild Justice'.