Damn! Hell!! Poop!!!
When I found out, I said stronger and louder words than above.
Must not have secured the LH Pannier properly before a short ride this morning, noticed at Kinglake it was missing, re-traced my ride, looking carefully, nothing found. Returned home and re-traced my steps, this time in the car, still no luck. Reported to a couple of local Police Stations - not sure if that will yield any success.
So, before I scan Gumtree and eBay any further, if anyone out there in OzSTOC land has one they don't need, I pay reasonable costs to buy, plus postage & handling.