... If something was done that isn't compliant with fire safety then you probably won't have a valid fire cert (and possibly no fire cert at all) and in the event of a fire involving that part of the building, you could find your insurance reluctant to pay out...
Just to clarify on this, and not to take away from the importance of fire safety, but as a house* it's not likely to have a fire safety cert as fire safety certs wouldn't be required for this sort of building. Compliance with relevant building regulations for fire (such as applied when the house was built or the work was done) is still required and may be available in an opinion of compliance, but a fire safety cert is not. Just saying this in case OP goes looking for another piece of paper that's never going to be findable!
*assuming it's a single family dwelling that's not a flat.