It was lucky to be sure, but I still think some credit is due. One arguable error that the Government has made throughout the pandemic is to continually be behind the science in its policy decisions, and more generally has been reacting to events rather than anticipating them. It would suck if they are also criticised for being proactive, especially when hindsight even supports that decision.
Perhaps, too, if the decision turned out to have been wrong, the sense I'm getting from the efficiency of the vaccination rollout is that it could have been (fairly) quickly reversed if needed.