Beware of "unlisted" Georgian mansions! If it's any good (even in a poor state), why is it not listed? I only mention this as when we bought ours (also a Georgian country house requiring refurbishment) it was, apparently, unlisted. The owners said it was unlisted. The estate agents said it was unlisted. My solicitors said it was unlisted. But I still didn't believe them so went to the Council myself to check in person. They assured me it was unlisted. So I proceeded to buy it, safe in the knowledge we could do the work it required.
In went the planning application, and back came the refusal. The reason? "It's Listed".
Off to the lawyers I went, and after a bit if argy-bargy with the insurance company acting for the Council (who admitted it was their fault for not having their Listed Building register up to date and accurate) I accepted an out-of-court settlement payment. But of course, I still couldn't do some of the work I originally planned. That said, it's a nice house and 9 years on we're still pleased we bought it.
Just thought it worth mentioning!