IFMagazine have an interview with Burn Gorman available to read online here! In it Burn talks about his character's development, how each of the Torchwood team look after each other more, and he even hints that there is another Doctor Who character crossing over into Torchwood:
I can tell you that there are definitely, it may be for the more obsessive fans, but there are crossovers from DOCTOR WHO. Obviously, there’s Freema [Agyeman] and towards the end of the season there are some, I don’t want to say old friends, but certainly there are some familiar faces, yeah. I would say that.