So, you'll have to make do with this photo from the brochure. It is subject to copyright but as it's advertising the house, perhaps I won't be sent to the tower?
It was an excellent, well organised tour with very knowledgable staff. A party left the entrance every 15 minutes and followed a route which ensured no two parties ever crossed one another. There was an 'airport-style' security scanner at the entrance before you were marshalled into the correct line for the next scheduled departure. One nice touch was a registration system for free unlimited admission for the next year (during open months obviously). Naturally, there was a very tasteful shop which you were encouraged to visit.