To change your name after marriage, you will need to obtain a certified copy of your marriage certificate from Births,Deaths and Marriages. The certificate issued allows you to change your name into your married name at banks, all government departments, motor registry, obtain a passport.
The Ceremonial Marriage certificate issued by your celebrant is not accepted as sufficient proof of marriage. It is an easy process. On my website, go to Births, Deaths, and Marriages website link.You will find the form required. Fill in and provide photo copies of identification as stated. These photo copies need to be sighted by your celebrant. You pay the certificate fee by credit card to Births, Deaths and Marriages.
I then send the change of name documents, together with my paperwork to Births,Deaths and Marriages where the marriage is registered and certified marriage certificate is sent to you.