For a lesson on how to create a charming indoor/outdoor dining area for summer nights, we take you to a small backyard in London’s Crofton Park neighborhood. There food writer Mina Holland and musician Freddie Denham-Webb have created an oasis in the city—complete with an American-style Big Green Egg grill. What prompted the American barbecue invasion? “We’re on a street of what I figure were quite experimental Victorian houses. Ours is a purpose-built maisonette, and opposite there are cleverly laid-out cottages. It feels like it was a bit of a testing ground for small-space living,” Holland told The Modern House.…