[spoilers] Spooks Locations

[Tea Lady]

I don't think we have this one yet. The Havensworth Hotel in 5.4 is Wrotham Park, Barnet, Hertfordshire. Well the exterior shots anyway.

   

http://www.wrothampark.com/

As for the interior shots, I think the corridor/room scenes were filmed in a different place to where the reception area/staircase scenes were filmed. In one scene where Adam is looking down over the staircase, carved into the walls are the names "Wheatstone" "Napier" and "Wolf" with some dates, 1791 and 1836. Now these chaps seem to be physics/astronomy type peoples. I have drawn a blank so far looking at places in London such as the Science Museum, V&A etc.