It is NOT usually beneficial to purchase the frrehold of your leasehold building. The savings are minimal and the effort and cost can be horrendous. If it is a leasehold property then the freeholder arranges things such as collection of ground rent, buildings insurance, etc. If the ground rent you are being asked to pay is extraordinary then it may be worthwhile to buy the freehold.
However if there was a great profit to be had for little work in owning the freehold then it wouldn't be for sale!
If you are obtaining a mortgage for this through a mortgage adviser then they will be able to assist you in the best course of action.