I'm with Dulwich Dental Clinic by the post office, on the lane. Haven't had to go for a while but they have been superb in the past when I have needed them quickly. Dr. Tremaine in particular is a terrific bloke. Regarding the King's dental hosp, they don't do walk ins any more, you do have to be referred through 111 sadly. Lots of people in the same boat, hope it gets better