I saw something suggesting there is a Martini bar at that pool in Shanghai so that seems to work out!
Do you remember the clapperboard titled "Dry Martini"? Very probably that scene is really set in Shanghai...
Look here: Orion Lee ,Shanghai bartender
http://www.castingca....php?uid=226484
MI6 suggested that – I think they'd seen the clapperboard with the bar in the background and then the filming at the pool and put 2 and 2 together. However, I think they are separate scenes; the clapper was from the day before anyway and they were not filming at the spa that day. Confusion was caused by the notice saying that the film makers were using the spa that day, but that was for setting-up for the next day - if you see what I mean.
MI6 also seemed to think that the blackouts on the pool windows suggested that it would not be in London. But there were blackouts on all the windows during the day, but they were obviously taken down at night, otherwise the press spy photos could not have been taken through the windows. I’d suggest that the blackouts were there because the scene is at night but large parts were filmed during daylight.