HOUSE was built pre 63, at rear ,theres ,a kitchen,and room,extension all wood, that were built, say 1950, house built 1920, classic red brick,terrace,bricks ,mortar,front of house
similar to this
so at rear,40total area, per cent of house ,is wood extension .
the new room would be on top of kitchen, approx,
14ft from rear wall.theres a yard a rear ,14ft x 12ft approx,
with concrete ,walls on 3 sides.the room would be built ontop of kitchen,
so distance is the same,eg 14ft from wall ,extension,kitchen to rear wall.
i think you are implying that to build without planning permission
there must be x feet distance each side ,
from new room to boundary wall on the right, and on the left ,
ie you cant build onto boundary walls ,with permission.
OBviously you could build anything, pre 63,
no planning permission needed ,
for existing room, kitchen.
and on the left.
ill post a drawing later to give more info.