The big thing about Thirteen Coins is that it's open all the time, like 24-hours. Perhaps that's why I love it, because a country that eats at five-thirty and a Brit that doesn't start thinking about food until eight-thirty are often incompatible.
I like the idea that I could go in and order oysters at two-thirty in the morning. I like the idea that I could tuck into a t-bone steak, served by a waiter in a bow tie, as the sun comes up. Of course it never happens, and I usually end up going to the Coins at reasonable times, but at least I don't have to worry that they're going to start hoovering up around me.
Going to the Coins should be done as a couple. Groups of three or larger are accomodated in booths with, surprise surprise, thirteen coins imbedded in the table, but the real joy of eating at this restaurant is sitting at the bar. Huge chairs ensure privacy, and there's nothing quite like watching your food being prepared.
The Coins is expensive, and the food isn't always that special - with the exception of the Monkfish which is truly the best I have ever tasted - but the point about the place is its novelty, and that's worth the price alone.
BTW, the area around Thirteen Coins ain't that great, so get a cab.