When I was an LBO manager back in the day, I remember the annual nightmare afternoon of a busy summer Friday or Saturday when Newmarket, Newbury and Newcastle all decided to race on the same day
I developed my own three-letter codes for courses early in punting life and those above are NWM, NWB and NWC but Newton Abbot is NAB. Bath BTH, Carlisle CLS, Cheltenham CHL, Chepstow CHP, Ffos Las FFS, Market Rasen MRA, Sedgefield SEG, Southwell STH, Wetherby WTH, Wincanton WNC and Wolverhampton WLV, with all others being simply the first three letters of the name, though Chelmsford would probably have to be CHM but it doesn’t feature in my records having never been scrawled on a betting slip nor clicked online