Hi Japitts, thanks for replying.
To clarify, I meant connecting the old TV box to the same terminal which the faulty V6 box is connected to, not to reactivate the redundant terminal.
It's in progress, and the Tivo box seems to have been able to connect to download a software update which is now installing. I'll let you know how I get on, but one thing from this experience is that despite the nostalgia of pulling the old box from the cupboard, its still a ghastly piece of hardware!