Any word yet on when the over 50's are due for vaccination?
Using most recent ONS estimate for population, there are around 7.5 million people in England aged between 50-59.
Given the vaccine has just been extended to all those over 60, and that there's around 3.1 million people aged 60-64, you can make a rough estimate that there will be up to a maximum of 10.6 million people to vaccinate (to get to a point of all over 50s having their vaccine).
So for example, if there are 500,000 doses a day, and say 20% are second doses (so 400,000 1st doses a day) it'd take 26.5 days to get through those age groups.
Short answer, probably within 4 weeks.
[ONS source
here]