They extended their invitation to include the "eligible" from anywhere in Bolton at lunchtime, then for the final hour or so of the day they dropped the word eligible. They're repeating the mass walk-up vaccination plan again tomorrow. As you say, the point is to get doses into people.
It will be too late for some (as the vaccine takes two or three weeks to kick in) but it may save the lives of others and it may slow the spread, which potentially will help everyone.
The stats at the moment show that it's still concentrated in the younger age groups:
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You can see it on the latest government heat map as well.