Hello!
Please see your trigger attached.
Regarding this condition:
Australia
Horse racing: gallops and harness/trots
Unfortunately BetFair does not provide any consistent means to identify the type of an Australian market. You will have to add all AUS markets (use the attached Market Locator's search template) and then manually sift through them in order to delete the ones you don't want to bet in.
You did not specify the type of bet and the market where you want to bet, but I assumed it was "back on the favourite in the win market". If not, let me know and try to be very specific.
In order for the triggers to work correctly, you need to refresh both win and place markets of each race where you want to bet.
Make sure you've tested the trigger in Test Mode.