You can join AOPA without paying for an aircrew card: In my experience you can occasionally get car hire discounts with the aircrew card but on the hop hotel discounts don't come so easily.
Surely the purpose of joining AOPA UK is not to see how many freebees you can wangle but to boost membership so that AOPA can become a worthy organisation to represent UK GA in the same way as US AOPA looks after its own.
A big increase in new blood into AOPA UK might stir some of the older brigade.
Cusco