For nearly three years, Thorsten and I have watched and listened to the exercise classes happening in Kingston Frost Park behind our Brixton house. We walked past many times and spoke to Dennis Dlomo, the coach, who greets everyone passing by and invites them to join. I heard the classes every morning and afternoon while typing on my laptop in my home office. But we didn’t get up the courage to actually join Dennis Dlomo’s Fantastic Fitness Club (the word “fantastic” is my own addition) until last month.