Neighbours building extension - what about our freshly plastered walls?

[Superarchie]

We're in a terraced house and our neighbours on one side are in the process of getting planning permission to do their side return extension.
The extension looks great on the plans, and as it's on the other side of the house to us it won't really affect us once it's built.
Our houses are joined all along one side, and within the last year we have had much of the wall that backs against their house replastered and repainted, including the kitchen which is where the works will be done. It all looks pristine now.
I gather that a side return extension is a big job with foundations being laid etc.
I am concerned that the drilling will cause cracks in our walls - is this a possibility? If so, does the neighbour have any responsibility to repair? How do we proceed?
Thoughts and experiences much appreciated!

This is what the party wall act is for. If they are doing work to your party (shared) wall, or digging foundations near it, they will need to formally inform you and allow you to appoint a surveyor to act on your behalf, who they pay for. If the surveyor says that damage has been done to your house, your neighbours pay up.

But if all the digging is on the other side of their house, you might not be close enough for a formal agreement to be required.

We were the people doing the work, and it was all fine except that our neighbours surveyor made our builder clean some gunk off their downpipe.

Are they digging within 3m of your boundary? If yes then party wall will cover it. If not then not a lot you can do. We had new plaster I a new house and about 10m away beholder a used pile drivers? Scary moist things to hammer rods into the ground. Not even a hairline crack.

There is no need to appoint a parts all surveyor as this is expensive for your neighbour. Just take lots if photos beforehand showing your lovely new walls. The party wall act will still cover you and you won't upset your neighbour. Beware that is quite normal for your new plaster to develop hairline cracks anyway as it dries out!

No, you probably don't need to appoint surveyors - but the PWA allows for it if you want to. And it also sets out the situations in which you must be notified before work can commence.