-
Most relevant things to look at are the permitted development guideline. pdf.- to decide if you need full planning - if so - the local council's SPG (residential design guide).is next. Different councils have different rules for boundary wall height. some as low as 2.6m. "Rights to light" is separate to planning legislation - its civil law i think. The borough will have a standard for what's acceptable on a side return they are considering loss of outlook, privacy, amenity - generally for habitable rooms only.
Sheppz-
Thanks this is really helpful. It turns out most of where I live has a section 4 (however our house is one street outside of it) and a conservation area, we are just outside of that too. So that's a good start.
No-one has had anything similar that I can find in planning if anything, most have the classic ugly square flat roof box straight off the back, and have left the side return, that I can see.
I've found the equivalent residential design guide and for single storey rear extensions close to boundary we can go 3m it looks like.
It's a bit elementary at the moment, but being able to open up the back of the house, fill the side and widen the kitchen would change it from a house we might stay in, into a house we would stay in for good.
mustardbeak
Now franticly googling side returns, would be game changing for our house, the back end is very Victorian and disjointed from the garden