Race betting and horse prices Interesting.
A couple more points if I may.
Backed horses will often drift on course 10-15 mins before the off. This is because on course bookies don’t have the liabilities at higher prices.
You mentioned one horse being backed in as well as your 6/1 chance. One reason they don’t always drift back out is that Betfair will average a 102% book whereas on course (especially night meetings with 15 punters there) will be closer to 130%
Finally did you know Bet365 run the horse racing part of their site as a loss leader. If you can’t win betting with them and their offers you have no chance.