It's a configuration change, it won't take long.
EDIT: SVLAN 'upgrade'? Que?
EDIT2: Never mind, I see some people aren't in one. This is something that will not improve your service but is useful to operators in segmenting traffic, especially if they plan on delivering a voice or TV service over your fibre service.
Operators can do it themselves via their software interfaces to Openreach, and downtime should be extremely minimal.
Edited by Ignitionnet (Mon 15-Jul-13 20:24:19)