That is my question too. I don't know about how planning works so it's a genuine question to those that do.

Just a quick look around the main things are below- a few of which I've been on the end of when extending properties over the years.

Whether the neighbours raise any objections

Whether the proposed design is of good quality and in keeping with surrounding properties

What impact your proposed development will have on your neighbours and the environment - for example through loss of light or loss of privacy. How your development would affect the surrounding area, eg if it would create lots more traffic

The number, size, layout, siting and external appearance of buildings

The infrastructure available, eg roads and water supply

Any landscaping needs

What you want to use the development for.

There's a website here that lists a big list of things.

rlhttps://www.richmond.gov.uk/what_is_a_valid_objection_to_a_planning_applicationrl

So looking at that there’s no showstopper regarding planning.

No idea about planning but Fishermanscap does on the surface post a lot like Vasty and certainly has the attitude, who was it that always liked to superimpose "footprints" onto Google maps? Hmmm.

I actually can see what fishermancap take on this and it is possible to do but there's several other things to take account of and the one main one is cost, I can see it costing and taking far more time to develop