It sounds like the work is being done on the QT.
One thing to remember is if you don't allow them to do any work from your side of the boundary is you may end up with a poorly pointed wall that looks untidy that you have to see everyday and your neighbour won't care about as they can't see it.
As much of a pain as it is it can be allowing them on your land to build something you don't agree with it can be for the best to ensure what is on your side is of a good standard and doesn't detract from your property
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