@footflaps I thought the new Avios didn’t expire, IME the new system is much better than the old. Upgrades do depend on timing, for busy periods/routes you do have to book well in advance. I use BA for holidays more than the budget airlines not least as extra luggage allowance and sports kit (skis/bike etc) go free.
I can answer the question on the wine as we tend to buy most of ours direct from the producer when on holiday in France, in many cases 50%-70% cheaper than shops (not least due to UK duty). You can’t do these trips with a plane as you cannot fit 200 bottles into your luggage !
As a final point, I think (needs checking) you can invite a friend to be part of your friends/famliy group then they can spend your miles and they can pay you something for them