Steve983 - 4 hours ago »
So to sum up so far, it seems I need a new Humax box to solve some problems and a new aerial to solve others. I'll talk to an aerial installer to get his advice before I do anything. The trouble with them is that whatever you say they always want to sell you a new aerial!
If it was me, I'd do it the other way around. First buy a new PVR, and try it out. That should clear up the PVR-related problems, and reveal any aerial-related problems more clearly. You might find it's not worth calling out an installer. Sky News, for instance, sometimes falls off my Freeview tuners, but it's usually weather-related. Probably more common around the Solent than in South London where I live.