You could try arguing they should be not permitted to close the gap between the properties, it may work if the other houses near by are generally well spaced.
Some years back - maybe 200x - someone bought the old house house next door to us, most houses in our road are relatively modern, detached, and generally spaced out. The new owner wanted to build a new house and approach us with the plans. I was quite happy, provide he maintained the gap etc and when I mentioned this I’m sure he commented the planning people had told him this would be required. I never measured the new gap but, if it did change, I can’t tell.
Conversely, our previous house, a semi, only had a narrow gap to the next house. I think that had been extended in the 60s but, while some houses near by were spaced, others were not. It was never an issue to us, it was like that when we bought it, there were no windows etc, or maintenance issues. Our neighbour was amiable etc so we never had an issue.
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