I have an 1837 marriage at St Andrews Scots Church which is from the parish registers and simply says
Presbyterian Church Marriages for St Andrew’s Scot’s Church, Sydney in the County of Cumberland for the year 1837 
Married by John McGarvie of Sydney, NSWales, minister of St Andrew’s Church there
I think  the original Scots church in Sydney was completed in 1826 - from a book about John Dunmore Lang 
By the middle of 1826 the building was finished though not yet paid for. The formal opening occurred on 16 JulyI assume St Andrews was a different one if it was built in 1834? As Ruskie mentioned - there seemed o be a number of them. Until I read the comment by Cass, i thought my 1837 marriage was in the original  
 
  
Trish