Any advise following visit by planning enforcement?

[V8 GMS]

Anyone had any experience of this and can offer advice please:
My neighbours have complained about the height of the extension I'm building, and the visit yesterday confirmed the builders are going about 10cm above what they should have done (from planning permission).

I can come down a bit fairly easily but not necessarily all the way into compliance with taking the roof off!

I can probably convince myself it wouldn't be proportionate for the council to take further action etc... but then they just might...

Keen to seek the path that leads to least disruption and/or added costs?

Thanks in advance.

[V8 GMS]

Thanks for the good info.
Yes its being done under planning.

I gather there are implications of applying for a variation, if it isn't approved, that I'd have to take it back to the specified height anyway (having spent more money/time on plans etc).

Can I ask how things doffer for permitted development. I've just done my attic under PD, but with neoghbours apparently on the war path, I'm half expecting another knock on the door to discuss this (but that wasn't considered during yesterday's visit).

Thanks a lot.

[V8 GMS]

Thanks both - much appreciated.

Its currently only 5cm over the plans because builder used 6" insulation (rather than the 4") before the riof went on. However I know I need an edge of coping stones (or similar) along the leading edge, which was never drawn on plans - so there's a bit more to add.

I think the neighbours who are retired (and stay at home most days) and have lived there quietly for 25 years, have been worn down over time by the noise from the builders. I've made loads of effort to keep them onside, but unfortunately I think they're at their wits end which has led to thier current behaviour - I wait to see what else they've complained about (probably keeping a diary of when my kids are making noise playing!).