Remortgaging b2l problem

[Craigybaby69]

Hi folks, I've been an accidental landlord for 12 years, finally got round to remortgaging for the first time. Had some previous trouble getting accepted by nat west but now I'm getting somewhere with another lender. The sticking point is the lenders conveyancers are insisting on seeing form AT5 as my flat is in Scotland. My letting agent does not retain a copy of the AT5 but does have a signed document to say the tenants were served with an AT5, but the conveyancer isn't playing ball....so anyone got any advice please? Approach the lender and see if they can tell the conveyancer to stop being so silly? Ask for it to be escalated at the conveyancer to a more senior person who can use individual consideration and not just follow the tick box process?
Appreciate any ideas, thoughts or similar experience any of you have had please
Regards Craig