I understand, the position today is, the council have to legally extend your lease but you legally have to follow the process below (which I have recently done myself)
1. Appoint a solicitor to represent me and service the Section 42 notice on Camden Council.
2. Pay £135 and £450 to Camden Council (as detailed above) so they can get there own valuation of the premium required to extend the lease
3. Appoint a RICS surveyor to value the “premium of extending the lease” on my behalf
4. If the surveyor for Camden Council and myself have different figures then there maybe some negotiation over the premium of extending the lease.
5. Pay the premium lease extension.
To be honest the online calculators such as the one below give a very accurate figure for what it is likely to cost to extend your lease. http://lease-extensions.org.uk/calculator.html
There is a lot of talk in the media that they will reform the law so that lease extension premiums will be more reasonable however I know there are companies still actively looking to purchase freeholds for the leasehold extension premiums so Im not sure if this is likely to happen very soon. There is also the added consideration that every year you do not extend the lease the premium goes up!
Note when lease length drops below 80 years there is a marriage fee applied to the premium which can be very significant.
The costs are
Council legal and valuation fee – £450 and £135
Your own legal and valuation fee – approx. £450 and £750
Lease extension premium – see calculator above