In recent days, two maps have appeared which throw a bit more light on the state of the Lewisham housing market.
As you can see, South East London is the biggest beneficiary, which is to be expected given that it's still a relatively affordable area and HtB is aimed at people trying to get on the ladder. So far, 41 homes have been bought with Help to Buy backing.
Secondly, this one from City AM, examines how many homes in each borough might qualify for Labour's proposed Mansion Tax. Data from the Land Registry suggests only 12 houses in the borough would qualify, although that seems like a massive underestimate given current house prices. The Cator Estate alone must have more than that. Anyway, the key number is 23 - that's where Lewisham ranks in terms of London boroughs with £2m+ houses.