No, I am not related, but started looking for you, because that's what we do

They are quite easy to find on Ancestry etc, and I didn't want to go finding information you already know. The more information you have the more likely you are to figure out who/where a relative might be.
the marriage was at Aldershot, 21 Dec 1918
William George BUCK to Lucy Evelyn PETTY both age 23
W.G was a Soldier, residence Codford, Salisbury, father Harry Thomas BUCK deceased
Lucy residence 18 Cavendish Rd, Aldershot, father Wilma Ingram BATTY deceased (I have found him also as William Ingram BATTY)
But obviously if William Edward was their first child and they took him to Australia then immediate relatives (descendants of him and his sisters) are there.
And if William George was born in Australia - then his siblings etc were or are there too. I haven't looked at that part at all. There are other, much more skilled, Australian researchers hovering on Rootschat.
It would only be the connections of his mother we would be tracing in England in that immediate generation anyway.
There are a number of trees on Ancestry with the family in them with whom you could make contact.