@Rixington, you had a better result than I did at a dealers. I took my tubed Navigator rear wheel to the Triumph dealer in Conisborough. I took it to a Triumph dealer as I figured Triumph's have tubes, they'll know what they're doing.
They refused, saying they couldn't fit a tube to a motorbike wheel, I pointed out that they had several in the showroom with tubes in, he said they didn't.
I did it myself, I nipped and punctured the new tube, bought another and did it right. To make certain I fitted tubeless CBR 600 wheels.