Fractul (or Lichtenberg) wood burners are not safe, do not build or use

I’ve always been interested in music and hi-fi and always thought the best scenario for serious listening would be a dedicated sound-proof music room where you could listen at all hours of the night at any volume without disturbing anyone. A man cave for want of a better term.
I was lucky enough to buy a house with a large detached garage which the previous owner had built for his automotive engineering pursuits. At 13m x 5m, this is unusually large for where I live in London and would never get planning permission nowadays, of course.  
The garage is a single-storey prefab of concrete construction with concrete corrugated roof panels, which was common in the 70s. For many years, the garage was just a storage facility and rubbish dump until I finally got around to transforming it into a music room and art studio for my wife (always good to have a guise for spending large amounts of time on a DIY project – I’m doing this all for you, my darling).