I second German Market on the South Bank next to Millenium wheel. DH had his work flat near there and we loved it every year. Not a massive market, but also nicely not overcrowded. DD1 (aged3 last year) loved the old fashioned carousel that daddy joined her on and we got lots of lovely warm food and some nice gifts. Small-ish but personal.
oh DD1 liked millenium wheel too. We pointed out all the landmarks for her.
DD1 and I also did The Snowman at the Peacock Theatre last year (matinee was popular) - DD2 (1YO then) stayed at flat with daddy for the afternoon. It was brilliant and I highly recommend. Geared for kids ie nobody minds background kid noise, lots of lightup glow-in-the-dark snowmen torch thingies bought at the box office being waved around. A ballet company, but the kids were engrossed. Good for adults too, really lovely.
I didn't like Harrods or Hamley's. Like someone else said, they are just shops. They were absolutely mobbed and not fun for kids. DD1 was desperate to get out of Hamley's and go back to the park to see the swans
.
We love the science museum and the natural history museum - very kid orientated and interactive - esp science museum.
As for restaurants, I've BF in most of them
. They have all been really good catering for the kids so I'm racking my brains for a negative recommendation - nope can't think of one. Italian restaurants are super-friendly and just lovely with kids, especially the small business ones.
Princess Diana Memorial Playground in the North East of Kensington Gardens is superb. Free to get in. Fantastic big wooden pirate ship to scramble around, teepees, big musical things to hit and jump on, swing park, fort for running round etc etc. Just wrap up well and have emergency change of clothing to hand (some water fountain things there!)
I wished we had went to Winter wonderland in Hyde Park - heard such great reviews. That's on my list next time we go back.
Finally(!) if you're going into London by train, always book as early as possible and check the prices for first class. I have found booking very early is the cheapest way and sometimes there's not a big jump in price to first class.
Have a great time I'm so 