Any advice for a solo traveller in WTP London to Singapore?

I'm currently in 21K, as I'm planning to skip the first meal service and go straight to sleep, so I want to recline without bothering anyone behind me whilst they eat. But I also like to guzzle water during a long flight so will likely be popping to the loo constantly and disturbing my neighbour (although I am a reasonably thin woman, so am hoping I may be able to get out via the gap by the wall and round the back of the seat?) I'm also not keen on the lack of window.

Should I switch to 16B (or go for 16A when it's unblocked) for better aisle access and more legroom, even if I'll have to wait to recline?