confused67:I have had a quote for holiday home insurance where the underwriters will cover me but exclude any claims re subsidence. The house in question has nonprogressive historic cracks which I have always disclosed (including to my current insurer). Does this quote count as a "special term imposed" that I need to disclose in future to all insurers?

In short no. Where Insurers ask about special terms imposed this is where you have a policy with a particular company and due to claims or issues they impose terms for them to continue the Insurance. e.g. you have a claim for a theft and the Insurers impose a security requirement and an excess. It is basically a question to elicit whether an Insurer has applied terms to an existing policy.

In regard to your current issue, I am not sure it is wise to accept cover without subsidence. If the house has non progressive historic cracks and you have not been advised of any subsidence issues, then I cannot see why cover with subsidence could not be arranged. I presume you had a general survey when you purchased the house that notes the cracks and you have felt it necessary to mention to Insurers. Many houses have non progressive cracks, but they don't and never had any subsidence issues. If the report does not mention subsidence, then why mention the cracks ? If you want peace of mind obtain a structural engineers report (SER) to confirm the current position before you take out a policy without subsidence. With an up to date SER, you can evidence to Insurers that there is no current issue.