Mystery uniform, could this be Australian?

[michael1]

I have posted this elsewhere but so far to no avail. Someone has suggested the cap badge might be 1st Australian Lt Horse badge 1897/1903 worn by 3rd Australian Lt Horse up to 1912. The problem is he wears a trumpeter’s badge of a type worn only by engineer and artillery units and a grenade over his trade badge and chevrons, his aiguillette may be part of the regimental uniform but equally could signify a bandsman, I would date it circa 1906/12 and he appears to wear a 3 bar QSA, does anyone have any ideas if this is an Australian unit and if so which,
With thanks in anticipation, so far everyone is stumped