My plan, upon finding myself in London with a day off, was to indulge my inner Downton Abbey fan with a trip to Highclere Castle. The Jacobethan “country home” that housed the fictitious Grantham clan was, however, closed until spring so I decided to trudge from my friend’s flat in Barnes along the Thames footpath to the Royal Botanic Gardens at Kew instead.

As devoted anglophile, I hoped to find the sort of quintessential Englishness …