The tenure question used to be simple and is now the single most common reason a sale falls through in the last fortnight.

Ground rent

New leases carry a peppercorn rent. Older ones with doubling clauses are close to unmortgageable with several lenders, and a deed of variation takes months.

Service charge disclosure

Managing agents must now provide a standard annual statement. Ask for the last three before you exchange, not the last one.

The ninety-year line

Below eighty years the premium to extend climbs steeply because marriage value applies. If a lease is near ninety, start the clock now rather than at resale.