I have a flat in Westcliff-on-Sea, Essex, with 59 years left to run on the lease. I would like to extend the lease, but I do not know how long for, or what it is likely to cost. Could anybody out there give me some rough idea of the likely costs of extending the lease by 40 years, 66 years or 140 years. The approximate current value is £107,000, and the ground rent is £25 p.a.