[Stuart]

As I understand it, it doesn't matter whether the box is on standby or not. Mine certainly recieves updates, and is left on all the time.

The only reason I can think of that the box being in standby (which just turns off the video display and front panel - look at the output on the VCR scart for proof) would make a difference is if the box needed to shut down so that NTL could overwrite the software. NTL can do this anyway, and if need be, they reboot the box remotely.