The lease is really low, but i've been given a quote (from the freeholder) regarding the cost of renewing it. Even factoring in this extra cost it is still reasonable (for London).
Interesting. Clearly if the lease is below 80 years currently you'll find it hard to get a mortgage unless the extension is simultaneous with the transaction. The freeholder's quote may not include your legal costs to extend (were several £k when we did it)
If it's cheap even for the area then there's probably something wrong with it / it will go for well over asking.