I have tried my hand at trading the UK markets and the profits per race can be small in comparison to your stake, i was trading 1 tick movements with $200 stakes and would turn over $2000 a race for a $10 profit if i was lucky.

I tried the Aus market but the price movements were strange at times and would only suggest it for major race days.

It can be long hours in front of the screen watching the prices move and if a price went against you you had to make the decision to trade out with a loss, i never traded in-play but did get caught a couple times when the race started.