At the moment, they seem to be not letting those under 40 have AZ - cancelling appointments etc.
What perhaps they may do, is suggest to offer those under 40 a choice rather than a refusal - let them take AZ if they wish, but be allowed to still request an alternative if they are not comfortable.
This would prevent a drop in vaccine uptake. If those in their 40s are unhappy to take AZ, how are those in their 30s going to feel, having already been told the risk is higher.
Anyway, they said it’s not necessary at the moment but could change in the future. I wouldn’t panic just yet.