If you secure a lease option and want to turn the property into serviced accommodation (SA), does this mean the property owner would need to remortgage to get a mortgage that allows short-term lets, or would consent from the lender be enough?
No landlord you approach will have a mortgage that will permit SA usage. It is a highly specialised form of mortgage and which would only be in place if they already operate as SA. In addition, no standard mortgage lender will consent to SA usage, so you can assume that a new mortgage will be required.
Most lease option deals fall over at this point, as the landlord can’t be bothered with the hassle of that just so you can use their property. If they remain interested at the point it will quickly wane once they realise both the set up costs and the higher ongoing interest rate they are going to have to pay for years to come - all so they can let you use their property for SA.