Both tube mounts are what I call "P clips", though there's a more accurate term--a friend of mine always corrects me...but I don't listen to him...
Just type "P clip" into Google & you'll see all sorts of them. Many are white plastic, or black plastic, or black rubber over metal. They're often used for cable management. I had one broken on my Star Wars: Episode I neon tube. I couldn't find a clear replacement for that machine, so I just got white. Close enough. (or maybe the price of the clear wasn't worth it--I forget)
See pics. My right one's a little tweaked from the screw head twisting it when it was torqued down. Ideally, these should have a washer under the screw head to prevent this. Mine are a bit grungy but work fine. I did note that my tube had scooched a little to the right & scooched it back--my clips don't hold the tube tightly from axial scoochage--a bit of rubber or tape under a clip would help, if needed.
As for the tube, sorry, but I don't know. If you do find a good replacement, please post here. Mine could use a new one.
-Jason
IMG_20160125_184356_(resized).jpg