Prod the start button in the McLaren 720S and settle back for some automotive theatre. The carbon fibre pod in front of your eyes pivots through 90 degrees to reveal a cluster of digital instruments. In the centre, a portrait-style infotainment system comes to life as your shoulders vibrate to the launch cycle of the 4.0-litre, twin-turbo V8. Then an angry bark from two exhausts, mounted waist...