Sometimes placing a regular bet or an accumulator can get a bit tiresome. So why not change it up with a Lucky 15 at William Hill? The Lucky 15 is a unique bet. Special Multiples racecard & betting odds from William Hill. Free Racing Post spotlight & verdict on all horse racing. I tried to place an accumulator on 6 Season match bets with them today (bets on one team finishing the season higher than another), yet they.