Has anyone extended their leasehold agreement on their property?

[HeadFairy]

How do you go about it? Do you need to use a solicitor or can you do it yourself? How do you work out how much the extension should be? I still have about 84 years to go on mine, and I know that once you go under 80 years it's more expensive to extend, but what about if you have more than 80 years?

I'm only extending because if we sell in a couple of years or so when the market picks up again then I'd like to have a good long lease. I know people get a bit jittery if the lease is under 70 years and if I do it before we go below 80 years it's cheaper, hence doing it now. I did think it's probably the sort of thing I could do myself but would feel safer with a solicitor doing as I'd hate to cock it up and have problems further down the line. I'll probably get charged a fortune but for peace of mind....

Right... sorry not to be much help, am hoping someone else with far more knowledge and experience will come along in a bit for you!