Went last month to for a celebratory family light lunch. I've never been bothered before as you can't book and there are plenty of good places around where you can.
Why take a chance on a long wait for a table when you can just call somewhere else and book yourself in?
My kids love it here though. They persuaded me and we arrived at 1150 to secure a lunch table.
I've been to the H&F a few times over the years. When it first opened my wife and I used to go a lot. Then it got impossible to get in to without credit cards and twelve months notice. TK's food is well known to me and so I rolled back the years and had the fish (goujons) and the triple cooked chips. In my opinion these are the best triple cooked chips you can get. Dom Chapman does good ones at The Beehive. His old haunt The Royal Oak does too.
I also enjoyed the parfait and the chicken Kiev though the latter was too salty for me.
Service was excellent. Some good beer and cider options and the bill was very reasonable.