I think you should change your rules to void all in running bets where a horse is disqualified for having the wrong weight.  If you consider yesterday's race, the favourite carried 14 pounds less than its allotted weight.  It was virtually a certainty.  Unscrupulous connections could lay the first past the post and back the second past the post in running. This is a huge moral hazard.  This doesn't occur often so changing the in running rules wouldn't inconvenience customers very much, but would stop a potentially extremely high impact abuse.