Hi Anderton...
It starts again on its own - doesn't need any help from me. Tne track stops and starts on the screen exactly in sync with the audio too.
I've replaced the Behringer with the Focusrite Sapphire 40 and so far that seems to have sorted it out, but I still get a continuos low level cyclical burst of noise every 3 seconds, lasting about 300mS. With no tracks audible it is really annoying. Once track audio is "audible", it's not noticeable, but I'd like to know what's causing it.
As an excercise, I've used my M-Audio Firewire 410 as the A/D interface and its' just the same, so something in the PC doing it or the Firewire interface in the PC perhaps??