I find Teeney Weenies can get very busy, but it's great for a couple of hours... totally exhausts my 18month yr old, lovely coffee and snacks too... the lady who runs it is always very welcoming, helpful and friendly. Recently Singing Hands were there doing a free taster class, which was a nice little bonus.
I've never been to the Pod, but heard fab things. I took my little one to The Lollipop Club for the first time last week and it was excellent. Based in Richmond, in the ground of London Welsh Rugby Club,(
http://www.lollipopclub.co.uk) - they have a large bouncy castle and loads of Little Tikes toys.. worth also checking it out - it's open everyday, all day!