Looking for a suitable second hand amplifier...help.

[Al ears]

No doubt they've got the power consumption right down on those.
I think the earliest Sky digiboxes used about 20W (whether on or standby). That would be unthinkable now.

A bit outside this thread but one would hope so, have to keep them on for the missus.
Anyway, on with the OPs question.....

 

[Samd]

It is.
If you don't use them frequently it's best to switch them off anyway with today's energy costs....
The only thing left on standby in my house is the Sky Q boxes...
Failing that you cover one of the IR receivers with black insulation tape

I turn mine off automatically on a switch (TP-Link) routine at midnight and it stays off even on holidays safe in the knowledge that any schedule of recordings (F1 etc) will be treated by Sky Q as a Power Cut and when I then go to the failed recording, the box offers the download of the programme. Very efficient it is too,
I rudely mention that, assuming that is your reason for leaving on!!