Highgrove is the country house of the Prince of Wales. I write about Highgrove because, although it is not a restaurant, even of the wackiest kind — which can only make me fantasise that Ludwig of Bavaria opened a gay sauna in Neuschwanstein castle — the prince does admit strangers when he is not there and only when he is not there: on Burns Night for instance, or Mothering Sunday, and now, on St David’s Day: a black tie dinner for £95 per face including service.