I can't believe your trip is so close - I will also be reading along over the Easter break.
it is has been 18 odd years since we were in Europe, and we're there over April, and there was snow in London. There was no visibility from level one of the Eiffel Tower.
Another vote for the V&A - even if you just go though the clothing, the older pieces were so delicate. The science museum was also fun.