Alex McMillan is a player of hard rock and a lover of rocking hard.   Raised on a diet of guitar gods and double-denim ’70s hair bands, he is also a third generation motor mechanic.   His dad Trevor is my mechanic. And my dad’s. He’s been keeping our cars on the road – and in great nick – for years. It’s always a pleasure to chat to him. He keeps a box of old pennies next to the till, which he lets me fossick through whenever we finish up a “transaction”.   The Central Victorian business was built by Trevor’s father, and ‘the shed’ in which it is housed a metal wonderland filled with 8o years worth of screws, spanners, engineering equipment, toil,…