AIBU re our Summerhouse (with photo)

[thisisatempname]

I have NC and tried to crop the google earth photo to make it less identifying but if you recognise me please don't out me! I've put an X by our house.
We have lived here for about 10 years, get on with all the neighbours as we've lived in the area all our lives and either know them a long time or through their relatives. Neighbour on right side I went to school with their kids so know them well, neighbour on left side been there about 6 years, mainly keeps themselves to themselves and I don't really know them.
As you may see from the photo, our houses are all buiilt on a hill, so neighbour on right is a bit higher than us, we are a bit higher than our neighbour on left. There's a main road behind us (behind the path/pavement), and woodland opposite us (behind the houses there)
Neighbour on right side has a conservatory where he can see pretty much everything we are doing in our garden, but that doesn't actually bother us and isn't the issue. Just mentioning it in relation to what the issue now is.
We are now building a summer house out the back of our house, its against the back fence and the left fence. It will be a den for the DC to play in summer and potentially also a home office. We hope to add electricity and heating, cost dependent.
Neighbour on right has no issues and has kindly helped with the building. Neighbour on left said he was okay when DH informed him in advance of building. Now his wife is complaining about privacy and size of the summer house.
I'm not a mathematician but the summerhouse itself is not more than 2.5m. It is on decking. We had to build decking for it to sit on due to the fact we are on a hill and garden is sloped. Together with summerhouse and decking, DH says the measurements are 2.7m. Is the neighbour right that it is too big?
DH spoke to the summer house supplier in advance regarding summerhouse size and the decking and was assured no planning permission was required. We got a separate company to do the decking and they assured us everything was okay. We also spoke to a neighbour opposite who is an architect and did our garage conversion and deals with council all the time and she said she forsaw no issues. But I am worried about this woman next door. I don't even know her name, she just banged on the door when I was WFH and DH was out and shouted and swore about privacy.
Neighbour on left has an extremely overgrown front and back garden atm. Its been like that for months. Whole street talking about how unsightly it is and the residents association have been to speak to them and they said they'd cut it. I don't know if she blames me for that although it was the association that approached her, without me asking them too.
Our houses are all bought and mortgaged if that helps. We have an association that deals with upkeep of common ground and any other issues affecting the street.
Anyway apologies for long thread. Any advice on next steps and whether we are in the wrong would really help.

You can build a summerhouse — referred to in permitted development legislation as an outbuilding — with a twin pitched roof up to four metres in height that’s no more than 2.5 metres to the eaves, or of 2.5 metres with a flat roof, without planning permission.

any part that's a metre or less from the boundary is no higher than 2.5 metres

so it requires planning permission As it is 2.7 at the boundary?

The platform height counts towards the ridge height. Is your x in right spot as it looks beyond the fence, if so how is that land designated?

No idea why my post above has a line through part of it - not intentional

Not sure what you mean, I was just marking which house is mine. The land behind is managed by our association and we all contribute to its upkeep (most do, some don't and get legal letters as its part of the purchase agreement or something although it was a while ago we purchased!). We are quite a large street and that photo is just part of it.. There's a road behind that grassy area.

My misunderstanding. However your building must be pretty close to a boundary.

Ask the planning officer. I know someone who had to take down their shed.

Agree with this completely. Sounds to me like you will need planning permission for the shed given that the total height will be over 2.5m and how close its likely to be to your neighbours boundary.

But you are just as unreasonable for relying on strangers on the internet to advise you if you need planning permission as you were to rely on the sales person.

Check properly.

Hi, we had similar issues with our planning. We ended up getting a smaller pitched roof. Here's the plannnig guide that we used:

https://www.scottsofthrapston.co.uk/summerhouses-garden-buildings/planning-assistance/

Hope that helps!

I'd just ask the planning department rather than listening to the supplier.

This thread is months old, so hopefully the OP has it sorted now!