The one thing they don't mention which to me is obvious that is after this 6 weeks of mass roll out they will have to stop moving down priorities to give all these people their second dose.
That's end of March.
Or roll out next to priority groups by then and then it'll be another 3 months (June) before they've got to end of too 6 categories.
Ok, that'll be summer and if we follow last years pattern things will naturally improve then anyway. But they are cleverly avoiding pointing out what we face after the next 6 weeks.