Actually just found this, photos indoors are not allowed, i guess thats to stop flash photography and in case you are casing the gaff to rob it ! lol
Q. Where can I take photographs?
A. We welcome amateur photography out-of-doors at our properties. We regret that photography is not permitted indoors when houses are open to visitors. The use of mobile phones with built-in cameras is also not permitted indoors.
However, at most properties special arrangements can be made for interested amateurs (as well as volutary National Trust speakers, research students and academics) to take interior photographs by appointment outside normal opening hours.
Requests to arrange a mutually convenient appointment must be made in writing to the property concerned. Not all properties are able to offer this facility and those that do may make an admission charge (including Trust members).
All commercial photography and fliming requests must be channelled through the Broadcast and Media Liaison Officer. Telephone 01793 817400.