I have been looking at buying a flat which is basically a semi-detached house split into two flats. The ground floor flat that I am interested in, owns the freehold to the whole house. Is there any benefit in this? Does it actually mean anything if the lease is so long that you will never take back possession?
I assume that you are buying the leasehold with the freehold thrown in? Doesn't make too much difference where the leases are so long they're a virtual freehold anyway, but the owners of the upper lease may wish to be part owners of the freehold too. In theory if you own 100% of the freehold you could ultimately sell your leasehold interest and retain the freehold, but this is likely to involve nothing but hassle and unless the ground rents are high would probably not be worth it. When I sold my flat (where I owned the entire freehold too) I sold only the lease and then transferred the freehold into the joint names of both sets of leaseholders as this is what they all wanted.
IMO there may be some value to owning the freehold, particularly while you are living in one of the flats. You could ensure the building is properly maintained and insured (usually the freeholders responsibility) and the terms of the leases could also let you establish a realistic "sinking fund" for future repairs etc..
It would be in your power to have the lease(s) extended and the ground rent reduced to effectively zero which can sometimes add a little resale value to a flat.
The cost of this is, at best, a little extra work or, at worst, quite a lot of hassle.... (...been there... done that!!) It could all depend on how well you get on with the other leaseholder.