Heard from my friend today (31, perfectly healthy, not a key worker) that she got vaccinated this evening. She had left her details with a local pharmacy as last minute back up recipient, in case any of the booked in appointments cancelled - apparently once the pharmacy has taken a batch out of the fridge they need to use them or throw them away. Pharmacy called her 15 mins before closing to say there were some spares going and she popped straight in.
Sharing because it seems worth doing if you live close by to a pharmacy and are able to go in quickly at late notice! I'm surprised the government hasn't publicised this actually, there must be a lot of people in cities would be able to get to a centre quickly at short notice and it seems like it would be a really good way to minimise wastage/ speed the process up.