You shouldn't compare any of those maps with each other - look at how wildly the percentage ranges differ in each key, and they use the same shades of colour for totally different percentage groups in each map...
You're probably right about the Bangladeshi population, but these maps are totally misleading.
EDIT: You see, the pictures make it look like "whitey is running for the hills", but when you look closer, the bottom population range in the "White British" map is 8.7%-50%. This is a lot closer to the TOP population range of the other maps, and a wider range. So although, there has been an influx of immigrants to London, these graphics don't prove how much/little when compared to each other.
Also I was wondering, do these graphics show 1st generation immigrants only, or simply ethnicities? I mean, many of the Indian/Pakistani population would be 3rd or 4th generation by now?