I think you missed my last post, but the issue is fixed. Turns out the booster was intermittently dodgy - giving a 20db signal boost but killing the quality of it.
Swapping out that (plus the old aerial cable, which was also showing its age) gives a nice clear strong signal on the Aura and everywhere else. My HDHomerun's have also now gained a few extra channels as a result, so a win all round 
