John Saunders has a review of Murray Chandler's games and career atE Michael White wrote: ↑Thu Nov 12, 2020 11:52 pmit might be worth looking at Tony Kosten's record.
https://www.saund.co.uk/britbase/pgn/ch ... iewer.html
In it the results of a 1975 Kent Junior event are quoted as
Kosten's year of birth is 1958, so evidently playing outside of school chess at the age of 17.1st Kent Junior Chess Association Championship, Tunbridge Wells (27-28 Oct 1975, 18 players) - U18: 1 MC [sic] Chandler (Charlton) 4½/5*, 2 LT Canham 4 (Data given thus in BCM, Jan 1976, p15 & CHESS, Dec 1975, p99, though they also seem to think there was play on the 25th which would be inconsistent with MC playing the Southampton Open on that day) (results - 1 v MA Seton, 1 v AC Kosten, 1 v MCL Read, 1 v JJ Ady, ½ v LT Canham) (* The Kent U16 ran over six rounds so perhaps this was also out of six)