One of the forms used by solicitor's during property sales is the Seller's Property Information Form. There is no standard for this, but it would be very surprising if a question was not asked about either whether any such work has been done, and/or whether guarantees are in force covering such work.
I suggest you go back to your solicitor and ask what is contained in the sellers response to this form - you may even have the copy in this 'pack'.
Armed with that information, you can decide if someone has misled you.
However if the work has been done, the survey says the house is OK and you have a warranty in the event of a problem, I don't think you have a problem.