Amended approved planning - yes Ive been a little bit naughty

[Old Salt]

Whilst it may not apply in your case you might want to take note of this ruling

London couple ordered to tear down £80,000 extension and pay £200,000 legal bill in fight with neighbours — Evening Standard

Shabaz Ashraf and wife Shakira told to tear apart extension to their £700,000 London home - because it was built just over two inches too close to their neighbours’ house

apple.news

 

[shabbaranks]

Not quite the same building over your boundary compared to building well within your boundary just slightly longer than you planned for. But still...

 

[phatboy]

Slightly? Would you have felt your extension was 'slightly' shorter if it had been built 1400mm less than the approved planning?

Without seeing the plans, I can quite imagine why your neighbours are peeved, tbh!