Thanks again dudes, hopefully will be doing more of these in the near future as I've got heaps of ideas to test out!
It's perfect Russ, the joiners are fantastic, really sturdy and no wiggle in them at all, thanks heaps for all your efforts. There is noticeable sag in the tubes at 4.5m length with the camera mounted, but it's pretty managable and as you said, at walking pace it doesnt affect the image quality at all. I've got a wire support brace that is nearly done which I will use next time and hopefully I'll be able to go the full 6.5m!
Edit: Just noticed that at that angle my scoop looks friggin huge! Pedestrians beware, you'll be swallowed up!