Yep I was in touch with solicitor today, and they confirmed it’s not worth the hassle pursuing. Though, they did seem to be misinformed re the need for a contract; a contract is required to ‘negligent misrepresentation’ but not for ‘negligent misstatement’.
Excellent idea about passing on the details of the survey to the estate agent, that way they at least have an established obligation for future potential buyers. And I’ll definitely keep an eye on it with a mind to informing the eventual poor sod who takes it on.