Loud Music at Mother In Laws?

We're on holiday at mother in laws right now in Kent, UK and her neighbour (a 50 yo guy) plays LOUD sopyp 60s songs all day long. Its actually like being brainwashed or something, its so loud. Luckily we leave tonight for home and luckier still he is moving out soon. MIL is going deaf so cannot hear it and she plays her TV so loud he's probably retaliating for her noise! But lordy what do you do with such a problem? If we'd stayed another month, what would you have done?