Talked to Jim Cline (Tartan Guru) and he said that it sounds like the engine is idling lower than the force of the air windmilling the propeller causing it to sound like it wasn't running.
The clue was that the prop was still turning and it didn't burble on transition to level flight.
IT sounds like it might be the problem as it dosen't pick up any speed on the down lines at all. You really have to resist the urge to get on the throttle early to avoid a wing drop on the pull.
Time will tell, Thanks all
V-Snap