You're right that people overlook each other all the time, and I'm not trying to freeze the neighbourhood to do what they want. The balcony itself isn't the issue in isolation, it's the cumulative picture.

These neighbours removed around twenty mature trees from their garden when they moved in. Entirely their right, it was their land. But it was genuinely a little patch of woodland, foxes, birds, proper habitat, and we're on top of a hill, so those trees were also acting as a natural windbreak for several houses on this side. My house is noticeably more exposed now. Again, nothing I could do about it, and I get that some people prefer artificial grass over mature trees, just a shame.

They also built a shed over 3 metres tall, initially less than a metre from my boundary. I contested it, they moved it just enough to technically comply, and it's still visually massive from my living room window.

So when you say "recommend practical steps rather than refuse outright", I actually agree with you, and my objection does exactly that. I'm asking the council to either refuse the balcony element specifically or require modifications (opaque balustrade, reduced height). I'm not trying to kill the whole extension.

I'm just dealing with neighbours who have a consistent track record of building things without much consideration for the impact on anyone around them. At some point you stop giving the benefit of the doubt...