Agatha Christie needs charity?

I hugely admire the National Trust. Most of the time. The audacity of taking on properties and places in perpetuity for the benefit of us all. Who else would do it? Who could even face the budgeting for supplying dusters to a stately home for ten years let alone for ministering to its every need forever? It puts the concept of long term planning into perspective. This whole 'til the end of time thing does mean you have to make your decisions on what to take on and what to put aside very carefully indeed. As an ex National Trust regional committee member (an interesting but strange experience that made me feel very odd-one-out) I have appreciated what making these decisions mean and how rigorously endowments need to be considered before taking on new holdings of land or property.
Last month I received a letter from the Trust asking for a contribution towards the major restoration of Greenway, the only surviving home of Agatha Christie. Given to the Trust by Christie's family in 2000 its gardens have been open to the public for the last 6 years and now Christie's daughter and son-in-law have died, the house also belongs to the Trust. The repairs are estimated at £3.5million, with cataloguing and conserving adding a further £600,000.
If you were to ask me for a bit of dosh to save a piece of coast, or for an ancient forest I would cough up and be glad that the Trust can be counted on to do a job that no-one else will. But Agatha Christie's house? When Miss Marple and Hercule Poirot are household icons and murder mysteries are everyone's favourite bank holiday fare? Perhaps a commercial company such as Tussauds, owners of Warwick Castle, Alton Towers and the London Eye to name a few attractions, would be better placed to take on a project like this. But as it sits with the Trust, I would suggest that the commercial exploitation potential for the property must be huge; shouldn't the Trust be generating funding for this from the private sector and creating a surplus to contribute to other less immediately attractive projects? Humphh.