Well, well, seems persistence has paid off !
I now have Tivo coming (Oct 28th

) for the princely sum of £0 upfront, and then the standard +£3/month. I was kicking off a little as Tivo was always going to be No Installation fee, but with £49.99 Activation....the latest round of advertising was No Activation fee....but with £49.99 installation ! Complained for some time, and managed to illustrate that a new customer package was advertised with no activation or installation charge, and the Rep (retention/cancellations) advised that there was a cotnradiction in some web advertising and that "if you are telling me you have seen this" then I could get Tivo for no activation/installation
TBH, they really struggled to get this on for me, stating that the discounting on our account was truly phenomenal - better than staff, they reckon

- but there it is £49.90/month for the whole shebang of :
30Mb broadband
Cheapo phone package and standard line rental
XL TV
Tivo (500GB)
V+HD box (getting relocated to a different room as part of the Tivo deal for free !)
What a deal, well done Virgin !