Success in the end, my baggage was found after 5 days. But only after an enterprising young man who, having been sacked from his job as a lost baggage supervisor and replaced by a company that couldn't find their *ss with both hands, set up his own company to find baggage that airlines or their out sourced handling companies have no time, or cannot be bothered to, chase.
One thing learned from this whole episode was new to me after a lifetime of travelling. Qatar asked for a photograph of my bag, which luckily I found in my laptop, taken years ago. Mine is very unique, covered in stickers (yes, I know...). In the end that was how the above guy found it stuffed away in a customs shed.