I'd be very careful about taking some of the advice given here, if you don't own the property then it could bite you on the ass.
Before doing anything you need to speak to 2 people..
1/ The company/person you rent from ask what their noise policy is and what is acceptable / unacceptable. An angle grinder isn't worth losing your home over.
2/ Local environmental health, ask what their policy is, it may differ from the rental companys. Tell them what you are doing and get their advice.
Saying screw him and going gung ho could get you banned from using tools at your address, or having restrictions put on you.
I live in a maisonett like you and I'm positive it says in my agreement that you cannot carry out any vehicle restorations etc that cause excessive noise...so if you haven't already, then dig out your deeds and have a read.
I can only echo these sentiments.
The lease of the property will more than likely say that you can't carry out any vehicle repairs anywhere on the property. Even if it doesn't the lease will contain catch all covenant to not do anything on the property that becomes a nuisance to any other tenant in the building.
Your neighbour could complain to the freeholder/landlord who will be under and obligation to enforce the covenants on the lease against you or you landlord (if you are an under tenant occupying on an assured shorthold tenancy). If you are an under tenant your landlord will not be too pleased if the freeholder commences forfeiture proceedings against him or her.