I'm personally not aware that any evidence about the efficacy of the AZ vaccines in people >65 years has been released to date. The Lancet paper definitely didn't report any.
1/
https://www.thelancet.com/action/showPdf?pii=S0140-6736%2820%2932661-1

Some may feel that given the circumstances, the German authorities are overly cautious to restrict the use of AZ vaccine to age groups for whom there is evidence for efficacy/safety (i.e., 18-64 year olds).
2/ https://twitter.com/MattGarrahan/status/1354775315059380226

National medical regulators are expected to assess the robustness of the available evidence, and not to extrapolate efficacy/safety to demographic groups for which there is no data, irrespective of the urgency of the situation.
3/

I believe the German regulators might not have had much choice unless they had access to additional data (which doesn't seem to be the case). Then, governments don't tend to overrule recommendations by their public health advisors.
https://twitter.com/olivernmoody/status/1354781400071860230
4/

This is all suboptimal and the recent conflict between AZ and the EU over contractual obligation doesn't help. Though, the decision by the German authorities to restrict the AZ vaccine to the 18-64 age group looks far less political than some may suspect.
5/