Thanks for your reply.
As planning permission was not granted for the conversion, the "existing planning permission/use" of the building remains in place (ie as one single dwelling).
Terefore, no action will be taken by the Council if the property is used and occupied as a single dwelling. (The Council will only take enforcement action if the property is used in breach of the permitted use, which is as a single dwelling. Any action is taken against the owner of the property at the time the breach occurs).
As regards ***** ***** in order to create the 4 Leases, the Landlord/Freeholder (let's call him X) must have granted the 4 Leases to a third party or to himself plus a third party (let's call him Y), as a perso
an not grant themselves a Lease. Therefore, to enable you to proceed you will need X and Y to surrender all 4 Leases, so they in effect disappear and you are then left with just one Freehold Land Registry title. This can be done by X and Y entering into a Deed of Surrender of each of the Leases, which is then registered at the Land Registry, who will then close each of the Leasehold titles. Your Solicitor can request this happens before completion.
I am not sure why the 4 Leases have been created- it would be normal for planning permission to be granted for a conversion and then the Freeholder creates the individual Leases. Not sure, therefore, why the Freeholder granted the Leases before permission was granted!
Subject to the Leases being surrendered, any Mortgage Lender is only likely to lend once the property has been converted back to a single dwelling, and I note you are aware of this.
I hope this assists you and answers your question.