I'm looking for some advice on fitting some old twin trumpet air horns I have in the garage cupboard to my Defender.

Where is the best / easiest place to locate the compressor and horns on a current Defender. There doesn't seem to be a lot of spare room around the engine bay.

Is the stock horn relayed or do I need to fit a relay?
If so where is the easiest place to get a live feed for the relay?