I vaguely recall that there is not a precise time at which markets are made available on Betfair, although you will probably see them appear around the same part of the day each time. However, I am not sure of the specifics, so perhaps if you contact the Betfair help desk then they might be able to give you an estimate of the typical time of day at which each type of market is typically made available.
I have followed the advice and asked Betfair support; the answer was: " The more prominent the event the further in advance it will appear. EPL games are usually put up roughly a week in advance. "