I'm doing it at the momment. It's been really, really hard going fitting it on top of day to day SENCOing and my teaching commitment. Each module works out at about 5 weeks worth of dedicated work (suggested). I haven't done that (you know... the day job!) but I did have to devote two whole weeks over the summer to it, plus I've had about a week of working from home days on it, plus one day at weekends for a couple of months.
I've completed two modules and have one (a research project) and my portfolio to go. It is very academic. Far more so than anything I've done before.
I'd get started... if only because you will meet other new SENCOs to work with.