How many others are in the same building as you, or is it just yourself? If there are others a majority of you have to get involved in the aquisition.
The rules behind everything are quite complex. Chances are you will need a solicitor and a surveyor. Both need to be familiar with the enfranchisement processes. Solicitor makes sure the notices are done correctly along with other paperwork, whilst the surveyor for yourself, and the surveyor for the freeholder try to work out how much you should pay (there are rules to this).
With such a long length of lease, and negligible income, it's probably not worth the freeholder having it, but equally, it's not worth their effort and hassle to sell it. You may well incur costs to twist their arm in getting and keeping things moving.
Check out the web site :
www.lease-advice.org