My cousin (90 at the time) had a similar issue when the house next door was sold and the new owners had a huge extension built before they moved in.
There seems little help in a case like yours, especially as you say your council cannot help. However, there are a few things you could try.
Were you notified about next door's plans before any work started? If the work is substantial then surely the new neighbours must have applied for planning permission. I would contact your county council to enquire about that. There is such a thing as the Party Wall Act which covers damage to property and boundaries. I would do some research into that and see if that could help. In my area some solicitors offer a free 30 minute chat. Perhaps you could see if that's available where you live, failing that a Citizen's Advice Bureau will have some good advice.
The bottom line is that your fence and drive will have to be repaired or replaced. Don't be footing the bill for that yourself. Take photos and document evidence.
I can never understand why new neighbours behave like this. It hardly bodes well for good relations. Good luck and don't give in!!!
