Following 5 days of no signal on Input 1 and Input 2 and consequently no TV,
just called Sky and we went through a System Health check and LNB reset.

The upshot is that an engineer is coming out at no charge, but as a matter
of interest, the result code for the check was "W1H6" and the result on
Inputs 1 & 2 were "4WWW-WWWA"

Any pointers what these codes reveal?