I think it depends on the guide you get as to the extent of information provided. When I was there it centred more on how some of the restoration work was carried out by the Rothchild Foundation. There was little about the Spencer family - if you want to hear more of the Spencer family, I think it's better to visit Althorp, the family home of the Spencers. There is more atmosphere and information on the family and the house contents - paintings, furniture, etc.
You need to book ahead for a very information guided tour of the fabulously refurbished interior of Spencer House. Guide will provide a lot of history both of the original house and its owners and the restoration by Lord Rothschild. That’s it. Tour of the interior of the house.
I am not sure what you mean by things to do- you go on a guided tour round a small part of the house. If you are interested in Lady Diana, nothing here has any association with her. Much of the carving (eg fireplaces) is not what was originally there but has been moved to Althorp from which it can't be removed because the latter is now a listed building. But things have been faithfully copied. You see a library, where the huge mirror comes from Wynyard in County Durham, the books are a private collection and a set of engravings from 1752.
The dining room is magnificant and some of the furniture is original (on loan). There's quite a witty sculpture of Hercules (William Pitt) strangling serpents, whose heads of those of Lord North and Charles James Fox. Three pictures of deaths in battle- Wolfe, Bayard, Epaminondas.
The climax is the palm room, completely OTT with golden palms embracing white pillars .
You also see the staircase Hall and the music room, where I think the fabric chosen to cover the chairs is horrible. There are then two further large reception rooms with beautifully carved fireplaces, pictures and carpets. There are no bedrooms, servant's quarters or kitchens on display.
I think most children would be bored out of their brains and I wouldn't take one round.
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