What value will the cert be in reality?
If the EWI has been done a while, then maybe the entity is gone bang so what exactly is the surveyor worried about: his PI probably....
In addition the purpose of the cert is more to support the paper trail/tax aspects of the work, rather than provide any real comfort on the quality of the work.
Yes SEAI now do random inspections but for EWI, without invasive examination, the inspection is just to see was it actually done, with no checks on the materials used.
I would , as an building services engineer, be much, much more concerned about the quality of the work, the materials used and what state the house in in post the EWI, moisture and mould wise.
Re an executor sale, you are really buying as is so don't expect any sympathy from the vendor.
Ps, if it an issue for the bank, if so sceil eile.