John Leslie Landlick Lang - Any advice?

I have reached a dead end tracing my family history.My Great grandfather was John Leslie Landlick Lang who married Lousia Helena Ellen Giese in 1901 in Geraldton, WA, Australia.On his marriage certificate He claims to have been born in Liverpool, England in 1873 but all efforts to find his records or his parents(John Lang and Anna Wilner) have failed.

I have tried BDM England, Liverpoool Census records, Local resident and business directories for Liverpool at the time etc.Somehow, I think he was lying and that he was not born in Liverpool in 1873.There is absolutely no record of any Langs with this name in Liverpool between 1850 and 1900.

Any advice or information would be greatly appreciated as I am totally stumped as to where to go now.