There is a bottleneck.
F1 & F2s are the ones most people think of as junior doctors. Long hours, low pay. Over the next 7 days DD has four days of normal shifts then three nights, then straight onto her new rotation.
More medical school places have opened up but specialist training has not been expanded, so a bottleneck. There is only one training place for every four young doctors. Even GP training is hugely competitive. So because they were working long hours in F2 but need to do well in exams to get a training place it became normal to take a third year, either in a locum position (not the paid per hour locum position but a one year temp contract) or medical school teaching as a clinical training fellow.
But.a lot of the temp positions are now filled by Physicians Associates and they are absorbing some of the specialist training resource as well.
DD is very aware that at the end of her F2 she may have no choice but to move to Australia or to change career. She is lucky in that she also has an engineering degree. However she would much rather be a doctor.
Making it worse F1/F2 positions have been randomised so you can be sent anywhere in the UK. (We know one girl with top marks from Oxbridge, who has been sent to a rural hospital in NI whilst her fiance is in London.) Then specialist training is so hard to get that you then have to move wherever you can to get it - and presumably you also had to move to get the post-F2 locum/CTF work. No point working hard, and being good at your job. The NHS don't care. Training positions are open to applicants across the world, and presumably we are still recruiting consultants from overseas, so British doctors are simply replaced.
Pay was the issue for the BMA, and perhaps those junior doctors with secure training places. Not for F1/F2s. To be honest DD is working such long hours that she takes home plenty and has no time to spend it.