Hi
Trying to narrow it down. Perhaps check the program log for withdrawn runners.
I had a quick look at Monmore results:
16:18 5 ran 1 named non-runner
17:18 5 ran
all other races 6 ran
From Rules and Regs:
Greyhound racing
13.1 General
All bets (excluding those struck on ante-post and Australian licensed markets) are placed on trap numbers. Greyhound names are displayed for information purposes only.
Markets will be determined according to the official result at the time the track gives the result green light status, either in the form of an announcement or by display. Subsequent disqualifications, appeals or amendments to the result will be disregarded.
If a non-runner or reserve runner is declared, then all bets prior to the update of the market on Betfair will be void and all unmatched bets including ‘Take SP’ and ‘keep’ bets will be cancelled (except for certain SP bets as set out in Paragraph 10.5 of Part B above).
If there are no finishers in any race or any race is declared void before the official result is declared then all bets will be void.
If the scheduled venue is changed after the market has been loaded by Betfair, all bets will be void.
In ante-post markets, all bets on individual greyhounds stand whether the greyhound runs or not. All ante-post bets will be void if the competition is abandoned or the venue is change
From SP Rules and Regs:
10.5 Specific conditions for SP bets for non-runners in greyhound racing markets
ALL SP bets will stand so long as your trap selection is not vacant or after your bet placement a reserve runner is not subsequently entered to run from your trap selection.
ALL unmatched ‘Convert to SP’ bets will be cancelled when a reserve is added or a vacant trap removed.