Thanks for the list hackmum I'm sure as a series four virgin I have more, not least, in addition to Roz doing her hair one handed, how can Steve get to work now immaculately turned out as per usual?
I've got a weird theory going round in my head, but have to stress that it's based on nothing but my imagination and not having seen previous series, might be completely off the wall, but here goes. Roz has declared, to Hilton, that she loves her children. Nick in this episode shows his concern for them, but they both seem oddly detached from them. This may be because they're just not that important to the storyline or it might be because they're not their biological children. Roz's career break of five years clearly wasn't after the birth of either of them, so what if say they're her sibling's children and that sibling was killed, possibly as a result of some gangland thing - hence Nick's question about them being 'safe'
Could there be some back story about Roz and Nick being childless highflyers in the fields of corporate law and crime and they've somehow, maybe via Jimmy, become enmeshed in something dark and deep? This would also explain Roz's comments about her giving up things for the benefit of others. When you take a career break for your own children, you probably wouldn't phrase it like that, it's your own choice to look after them, not something you see as an obligation.
While I'm here can some officianado clue me up about Hilton please. The part really isn't well acted for me, and I'm amazed how he could've risen to such a rank. There must be a lot more to him than I can get from him this series.