Would that be near Highbury Tube stop? I come in via Tottenham Hale (if Maddies comes in, I think she'd be coming via Tottenham Hale too), then usually change onto the Victoria or Piccadilly to get into Central London.
Yes, if you wouldn't mind checking that out, it would be great. I'm particularly interested in whether they have segregated areas for little 'uns versus the over 3's or 4's, and how warm it is so I know how to dress Niall.
As a side note, our local play barn is really nice, just a bit on the chilly side. So I'd normally dress Niall in two pair of socks (no shoes allowed indoors) and a Gap sweatshirt -- then he's good to go!