Wow that looks bad,  I've had 2 reels of thermobore for about 2 years now and at high temperatures 50-75C but I do have the pressure (not flow) down as low as I can, I use a pressure switch rather than a controller to adjust the pressure.  I only recently had to chop a 6ft length off the end due to a burst, but that was probably from a gate.
How hot do you have it and what pressure?
Simon.