Well, very pleasant eng called today (3 day wait was all) and fixed the signal levels, the SA box is fine and I've still got it. He did bring a Samsung in with him though and we had a little laugh about the SA hopefully failing the Medic check
He did mention some rather interesting news about V+ boxes though, but as I can't see it mentioned anywhere else I am staying schtum for now as I don't want to get anyone into bother. Perhaps the techs will know what I'm on about.