Here in the US they have little ovulation tests. I bet they have them over there, too. They are sold right next to the pregnancy tests and look the same...
I bought them when trying for Sydney (3). You get about 7 of them in a pack. Around the time you think you should be fertile, you pee on the stick. It shows a line if you are ovulating...then it is 'go' time! If not, try again the next day...