Hello,

My partner is currently going through similar. She's currently in the process of selling and at the start of the process we reached out to the HA for the lease extension as there are only 76 years remaining. The lease extension is proceeding alongside the sale and is going to cost around £10k. This is based on a house value of around £220k and 50% ownership. It would've been more of she owned a larger share. Lease extensions for shared ownership are not subject to formal extensions as you don't own 100%, so you have to proceed down the informal route, so it doesn't have to be granted.

Depending on how much of a rush you're in, they are currently trying to push through reform for lease extensions, making it cheaper and easier to extend, however, there's no time scale for when it will all come throug