Funny thing about season 2 is that it made me start liking Yoshida (I found her just plainly annoying in season 1). As for Hecate, you won't see much of her in season 2 but in exchange, you'll see a lot of *spoiler*Hecate's sockpuppet*spoiler* so that may be a problem for you xD

I did watch a bit of BBC!Sherlock waaay back in the day, when season 1 was just being aired :|a I don't know what stopped me, though. I think it was the fact that they talk so fast, so I had trouble figuring out what they were saying xD; I'm sure there must be subs around by now, though.