Ideas for London with 9 & 4 year old?

[Shufflebumnessie]

We've booked a couple of nights in London for mid August. We're staying very close to the London Eye. What would you suggest for day 2 please?
Our plan is as follows:
Monday - AM - arrive in to Waterloo, leave bags at hotel, lunch.
PM - British Museum, Hamleys, Disney store, dinner.

Tues - we need ideas. Was thinking maybe a short boat trip or Platform 9 3/4 as DS is a huge Harry Potter fan but not sure. All suggestions welcome.

Wed - check out of hotel.
London Eye and Aquarium (paid for using Tesco Clubcard vouchers)
Train home later afternoon/early evening.

Thanks in advance.

I would get the Thames clipper down to the O2 and go on a return trip on the cable car and then back on the clipper and get off at greenwich for the maritime museum , cutty sark , greenwich park .

Sealife is near London eye, we happily spent a few hours there!

Shrek's Adventure, near to the London Eye, at their age they will love it.