hey, i was thinking the same too! glad to see i'm not the only person in the UK that can't wait for new episodes to air! Lol. Anyway to your domanda i think they will just mostra the grey's epi's not the other half to it that was in PP. If they don't then i bet they take it off air for awhile. Hopefully they don't cos i like watching it again on living. lol.
In the Sky Magazine there was a little blurb about Addison coming back to Grey's for the week it is going to be on. But I don't know how they are going to do it regarding the PrP episode, but the Grey's one is definitely going to be on.