How would building flats on top of the petrol station on London Road help the council make money to fund the building of social housing?

I assume this site is owned by Exxon-Mobile or some other private land owner, as is the Red Cross shop and Pizza Hut on London Road, which was granted planning permission for residential above. Nor do the council own the railway line. Network Rail would be the only company to make money out of building residential above the railway line, but for some reason they haven't done this on any sites I can think of on the network.

Can you explain how the council would make money from the development of these sites?

Some of the other ideas are great, but none of them address the actual concerns of residents in and around Eliot Bank. Lewisham Council / Lewisham Homes want to build everywhere they can. I'm sure this document will give them some new ideas, but that won't stop them wanting to build on a nice green space on Eliot Bank (especially since the market value so close to the Horniman is higher than in other locations, financially this site is very attractive to Lewisham Council / Homes).