I've gone for Bradley Branning (even though I don't watch Eastenders and have absolutely no idea what's going on)
Bradley is leaving, and I read an article from end of last year which they announced Bradley would be leaving "in a storyline written to celebrate the 25th anniversary of Eastenders", so makes sense to me
Although I guess even if that's what they meant at the time, could've been changed by now.
I put money on Bradley though so I hope it's him (don't know why I've bet on something I don't even watch! Maybe I have a problem..)