The insulation surveyor chap who visited us today drilled very small holes to assess if we already had it or not. The assumption beforehand was the main part of the house wouldn't, but the newer extension would. It transpired that neither part has it.Before we moved in to our house 20 years ago (Edwardian Terrace) I noticed some holes in the external wall. So, I asked the Conveyancing folk to ask the seller if it had cavity wall insulation. The response, rather bizarrely, was along the lines of 'that's up to the buyer to find out'. I still wonder what that meant, as how better to find out than ask the owner??! Still don't know if it has had it or not, but when we had an energy assessment a while back they told us it wouldn't be worth doing anyway, as we didn't have enough wall on that side of the house.