Was looking at the sticky -Your guide to spending Avios | 2014

>03 UuA on BA, AA, and IB flights
>UuA can also be applied to American Airlines and Iberia flights and/or tickets combining travel on either of these airlines plus BA.

I believe this is due to the joint business between BA/IB/AA?

BA is now in Joint business with JL and AY on flights from Europe to Japan, does that mean BA would now allow UuA on 1. BA coded JL metal to Japan 2. JL coded JL metal to Japan?

(Looks like if a ticket is purchased directly from BA, the JAL metal direct flight between London - Tokyo will be BA coded, but JAL metal from Tokyo to HEL/FRA/CDG will be JAL coded, only HEL/FRA/CDG to London flight will be BA coded, regardless of which metal)

Thank you