Anyone with experience extending leasehold agreement with Southwark Council?

We have only 65 years left on the leasehold of our flat, but Southwark refused to give us either a time or cost estimate for increasing the lease. They basically told us 'it'll cost what it costs, and will take as long as it takes'.

This seems very strange, but I've learnt to expect this sort of thing from Southwark Council.

Does anyone have any experience extending a lease that they'd be willing to share?

What are the expected costs? And how long does it usually take? And is there anything we should know/be aware of ahead of embarking on this leasehold extension?

Also, what's the impact on the value of a flat, with 65 years vs, say, 125 years?

Thanks in advance for any help :)

(P.S> In case it's relevant, the flat is a 2 bed duplex on Harold Estate)

I suggest that you contact The Leasehold Advisory Service www.lease-advice.org
they've got lots of very useful advice and you can also contact them durectly if needs be. I've found them helpful on other matters.