Well now. That was a bit of a palaver.
Sent MPN and Blood Cancer letters to GP, GP bounced me to the local NHS Trust in charge of vaccines. A lovely lady spent the next 48 hours getting a 3rd vaccine approved and booked me in at a walk in centre this morning.
Turned up and it took an hour and lots of phone calls to the NHS Trust to get the actual jab. The MPN and Blood Cancer letters were hugely helpful but their advice to other MPN patients is to get a letter from either GP or haematologist confirming that Pfizer is OK to receive after Astra Zeneca vaccines (if that is the case for you). They are mixing vaccines as a booster for 'normal' population but the walk in centre needed additional approval.
But it's done! Good luck all x