The position is actually much stronger than that, and has also been approved by the European Medicines Agency (and others worldwide).
It it this:
1) The AZ vaccine is effective across all age ranges, taken as a whole, as demonstrated in the phase 3 trial
2) There is insufficient evidence form the phase three trial to quantify the benefit in the over 65s standalone
3) The phase 2 study shows equivalent immune response (antibodies) in all age ranges
including the over 65s
4) The phase 2 results justify bridging efficacy from the general population to the over 65s cohort.
I've posted the antibody response against age before, but here it is again anyway
View attachment 9507