Hi,
As I now have a connect box, I changed the power saving mode on my Horizon box to ECO as I no longer use it for internet or landline access.
According to this link, scheduled recordings should still work in eco mode:
https://support-en.upc.ch/app/answers/detail/a_id/10472/~/power-saving-function-on-the-horizon-hd-recorder
However, a small amount of testing shows they don't.
EDIT ... I'm going to do some more testing as I'm sure an earlier recording did work despite the box being in standby. I'll post again in a day or so.