I have just ordered a Birth Certificate online from the UK. I am not 100% sure that its the person that i am researching but sometime you just have to take a chance in order to move on. To be honest its the first one that i have ordered in a while and i had to look through this web site for the Certificates Online Website.
I recommend that you first find the birth, death or marriage details at FreeBMD-Search. Make a note when looking at the record for the name of the District, the Vol and the page number as you will need this information when placing your order for the certificate. At the moment they are charging 9.25 pounds which works out to be about 15 dollars Australian
Here is the link for the FreeBMD-Search
This link will take you to the site