I’m always a bit wary when invited for the first time to a dinner party at a friend’s home; some of the least enjoyable social occasions I’ve ever attended have been misleadingly advertised as such. The inevitable email about “dietary requirements” has been duly responded to. You’ve muttered to yourself about the time (eight o’clock? Why so late?) and worked out that because your hosts (and I use that word advisedly) live on the other side of the city, you won’t be in bed before midnight.