Rest in peace.
Very sorry to see this. I met Mark when I was instructing a long time ago and he helped explain many of the mysteries of Air Traffic Control.He was a good bloke. Irreverent, funny and full of energy is how I remember him.
My sincere condolences to his family and friends. I hope his spirit is in the aviation section of Valhalla with a pint in his hand regaling friends with more funny stories.