Since it sounds like you are familiar with all of the rental companies, you know that you can trust them.
If there's three people, I'd go with 2 bedrooms. Even if it's 2 and you go with your son (I'm guessing that's who Jack is), I'd probably go with 2.
But I'm stubborn in this regard. I'm at the point in my life where I don't want to sleep with someone I don't normally sleep with, even if it is my family. And I even go as far as try to get at least two bathrooms if I can.
It'll depend on your finances but yeah, that's my preference.
Although Kensington is nice too.