Loading of Stalls

Why is the stall loading in this country so slow,if you watch American,Australian or French racing they are much quicker and mostly the races are off on time.Lots of horses are in the stalls for 4 minutes still waiting for the others to be loaded and they sometimes do not load the horses until near the off time.Surely if you have a 12 runner race or more they know it will take longer than 2 minutes to load them so why not start loading them early.Massive disadvantage for some horses to be sat in the stalls for so long.