Steak tartare, slow-roasted shoulder of lamb, venison burgers, chicken and tarragon pie. A quick glance at some of my favourite foods wouldn’t leave anyone in much doubt. I’m a carnivore, through and through. Yet, as of December 2015, I’ve done what I hadn’t countenanced since I was a teenager: I’ve gone vegetarian. It all started quite innocuously just over three years ago. I’d long been meticulous about not buying eggs from battery hens, yet while watching a particularly gruesome…