Switch over day was today.
DPD delivered the vf router yesterday (should have been last Wed, but I've been away). at about 0900 I was disconnected from Sky, about 30 minutes later I plugged in the vf router and waited. By about 10 the vf router has connected and was working (set the adult filter, etc)
Then phoned the vf tech team and they texted me my logon name and password.
Removed the DHCP options in my 2925 for Sky, and set the PPoE details, remembering to add an @broadband.vodafone.co.uk to the end of the username (email@example.com)
Initially I typed the details in and made a typo, so I forwarded the text to my PC and use the CLI to set the router, and then all was good.