L&C - Nationwide - Specialist Report Valuation?

PopcornPaws

We are applying for a mortgage through Nationwide via broker London & Country. We had our valuation conducted at the beginning of March and still haven't had our offer through. Our broker has told us that a "specialist report" had to be done. They said "the underwriters have assessed the specialist report and they have now gone back to the surveyors as they need an amended valuation report to confirm everything". None of it makes sense to me, they won't tell us what the specialist report was for. I have a friend who is a mortgage advisor who has said it sounds very odd because you would usually have to pay for a specialist report to be conducted and we've not been asked for any money for this. He thinks they might be stalling for something but no idea what. Any ideas on what any of this means and how much longer we should reasonably be expected to wait?! We had our offer accepted in October and it's taken L&C this long to get to this point, I'm so fed up of waiting