Surely that works now!? Set the tensioner up as close to the chainstay as you POSSIBLY can without the chain on, then replace the chain after it's set up.
Best natural I've ever ridden, best I've ever even seen!! Very few people on here know about it though..
EDIT: Oxford, Bristol or Plymouth for streetzz!
That was awesome flipp. Was a good ride, bit chilly!!! Glad you didn't put all of those failed gaps to front on the bench. Insanely good vid though. And camera quality is brilliant!