I concur about the lounge access. I've used the CCR before when traveling on an AA award ticket (into T3 on AA then on BA from T5).

I have never managed to find a way to have my BA number entered into a booking made with AA miles which led to the situation where a cabin crew member came along to all the golds on a domestic flight up to Scotland and welcomed them back and ignored me completely. Oh, the shame of it!!