Evyn
I did see the QSA to 5th SAust IB you were fortunate to be able to obtain. Medals to SAIB are certainly very uncommon on the market and I think you paid quite a fair price for the Burgess QSA. I had a look on the NAA site and found that his forenames were Stanley and Stephen; he was born in New South Wales, dark hair and complexion, was 20 YofA, stood 5'6" high, religion CofE, occupation Station Hand. The write-up on the JB Military Antiques site regarding Tpr. S.S.Burgess and the activities of the 5th, is, in my opinion, a very good narrative.
Some time ago, I contributed a couple of posts on a chap who served with 6th SAIB (Tpr. Mundy) and - as the 5th and 6th SAIB were merged in South Africa, it is possible you might get a little more general background from those posts.
Regards
IL.