I think we're supposed to believe that while Dean was out of Walford, he stayed local and met Shabnam in a club in Poplar, when she was out with Carly and Dawn. I don't buy it; had Dean been living with Stan, why had he not tried to intervene between him and Shirley before last year? They must have heard about Heather, which might have been a way in. Stan's also supposed to have known he's dying for 3 years; should this not have led to Dean's return if he was local all along, so Stan could ensure that Dean had someone when he was gone? Also, Carly and Dawn were quite in your face and suspicious people - would Shabnam really have been able to sleep with someone in club toilets without them noticing? I think Carly would have said something if she saw her brother who she hadn't seen in a while on a night out, or Dawn would have teased Shabam if she went AWOL on a night out.
Actually, scratch all that, Carly went abroad in early 2008, did she not? This obviously didn't happen before Carly left as Shabnam would have been heavily pregnant/been giving birth by the time she left.
Shirley being Mick's mother seemed a desperate attempt for an OMG moment, but at least that was credible, as was Buster being Dean's father too. This is Hollyoaks territory, and rather than copying Kat/Zoe story and Little Mo's story, we're now having a variation on Rebecca Fowler. I presume Royah will find her way back to Shabnam, despite having been adopted.
I remember thinking there was a contradiction in the dialogue on Friday; I'll watch it again and post back if I find it.