London Housing Design Guide-Possible Redevelopment Room Sizes

These are the recommended room sizes for new builds for London

1 Bed - 2 person 50 sqm
2 bed 3 persons 61 sqm
2 bed 4 persons 70 sqm.

Minimum Width in the main sitting area
2 person 23 Sqm
3 person 25 sqm
4 person 27 sqm
5 person 29 sqm

Minimum Area for a :
Single Bedroom : 8 sqm
Double Bedroom 12sqm

Or you can look at the London Housing Design Guide.

http://www.london.gov.uk/sites/default/files/Interim%20London%20Housing%20Design%20Guide.pdf

I would expect the redevelopment drawings are based on these sizes, but as we have not being shown detailed drawings , we can only make an assumption.