When you say "existing customers will have it fitted" you're not implying TiVo customers get free upgrades, surely?
We had the V6 installed last Tuesday free of charge with no change in our subscription either.
Was it an unprompted goodwill gesture or did you register interest? I noticed that you can't get it (for now?) if you have anything lower than their 100mb broadband service.
If your minimum contract with them has expired I dare say a call to them saying you're thinking about leaving might get them to upgrade it for free.
"Listen, we've all got something to bring to this conversation, but from now on what I think you should bring is silence." - Rimmer