Peabody is a registered social landlord. They are likely to house people who are already council tenants, or on a waiting list, or specific groups such as key workers. (Nurses, teachers etc)
Getting a council or Housing Association in central London is very very hard. There is huge demand and waiting lists in many boroughs run to 10 years or more. Its mainly done on a points system, so if you have children, are homeless or living in temporary housing, are unemployed and have health problems you will rack up points.
Having said that some social landlords let some properties out at close to market rents, say to help recover the cost of major repairs. So you could always ask.
Also if you request to go on a Council waiting list, even though you may never get to the top of it, it might help you qualify to buy a shared ownership property sometime in the future. (Though there are almost always income restrictions as well.)
The peabody has a website (http://www.peabody.org.uk/main/index.htm) that gives a lot of information about them & lists the properties they're renting out. Worth phoning though as I don't think it's very up to date.
Agree the Stamford street estate(backs onto Roupell st) looks very nice - much nicer than ours! Hope our one gets a similar makeover, but judging by their current financial situation it doesn't seem likely to be any time soon.