Ickworth is an odd house. To begin with, the Earl-Bishop, as Lord Hervey was known, began the house while living in Italy. Secondly, his art collection, which was supposed to be hung in the central rotunda, was seized by Napoleon. Finally, he never saw the completed house as he died in 1804. As a house, it just doesn't really hang together all that well--there is an awkwardness to it despite its impressive architectural qualities, the central rotunda being 105 high--which I can assure you is impressive. I visited the house sometime in the 1980's and felt that the purpose of the house was never quite defined. If you think about it, however, what the Earl-Bishop was doing, was creating an impressive art gallery and doing it in such a manner that allowed his own privacy in the houses built at the ends of the curved colonnaded walkways--although only one was used for the family, the other was used as an orangery. I am certain that I can say that it is unique among British country houses for its design--whether that is a good thing or a bad thing is something I don't care to judge. I will stick to my initial declaration that it is odd.
Odd certainly doesn't mean bad. If you think about Vanbrugh's massive designs at Castle Howard or Blenheim, I would prefer to be at Ickworth. I might, however, also separate the house from the colonnades and allow the rotunda to be an art gallery without the connecting walkways, or I might not wall the walkway in. The Queen's House in Greenwich is connected by open walkways to the pair of baroque buildings designed by Wren which flank Jones's Palladian villa and it seems to work extremely well. It might just be the density or confinement created by the two wings that makes Ickworth seem so uncomfortable. But don't get me wrong as it is worth visiting, not just for the art collection, but to see how the concept of the country house was such a personal expression. That the Earl-Bishop used an Italian designer, Antonio Asprucci, might also be unique among British country house design.
The furniture at Ickworth was largely kept by the family when the house was taken over by the National Trust and a lot of it was sold, usually privately but some also went to auction in the 1980's. If I remember correctly, most of it was Regency furniture and if I look at the photos in the links below, it is generally nice furniture, but not something I am aching to see again. I do remember noting that the doorways had wonderful overdoors with finely carved acanthus scroll supports. You can see similar ones in the National Gallery I believe. If you read my blogs regularly, you will see that I am reaching here in that a) I don't remember the interior that well and b) the singularity of the house is either something that piques your interest or dowsn't. I don't think I would return, but never say never as you can always be surprised. I am reminded of being in Salisbury Cathedral for a Christmas eve service--the place was packed and I couldn't hear or see much, but the carved stone memorials to worthies (people who gave enough to the Cathedral to warrant such a memorial) were absolutely fascinating and such exemplars of style. Ever since, I have visited cathedrals whenever I get to a town that has one. So if I happen to be in Suffolk with an hour or two to spare, Ickworth will be a re-visit.
https://www.google.com/search?sxsrf=ALeKk01U_cHd2dOghfO-KRJ_kII0AEeYdg:1612390339983&source=univ&tbm=isch&q=ickworth+house&sa=X&ved=2ahUKEwjttdCL3s7uAhVHQjABHZOcDX4QjJkEe The awkwardness of Ickworth.
https://www.google.com/search?q=national+Gallery+interior+shots+of+galleries&sxsrf=ALeKk00vgcqgHNRlzmlDHBHF0Z_g87lAHw:1613071964308&tbm=isch&source=iu&ictx=1&fir=dmloIHWw Interior shots.