AliExpress seems a crap. I've opened a Paypal case.
Well... at least the GoPro arm from ebay worked out ok. Now my long Dahon seatpost is free to use for purposes of defence of myself, wallet and GoPro camera containing video evidence of the event, should attempted robbery occur. I've lubricated it's quick release clamp, for battle readiness.
I took the opportunity provided by AliExpress's fsckup to extend a wire, for one of the two 1800LM headlights on my handlebar to be mounted to the Minoura extension instead. Like many people over 50, it's now further right. It's tilted down, and one of the two screws which secure this light to it's clamp could be removed, in order to swivel it clockwise. I'll see how it goes - the slightly backward sweep of my handlebar and that light's new position, could be enough for it's light to illuminate number plates passing much further away. It's very likely I'll need a third headlamp perched next to it, because of the narrowness of these 1800LM headlight's beams.
GPS tracker mounted to the pannier rack:
Further right - some do as they age: