Q: can i play all speakers on airplay

The ATV will only stream to one set of spaekers at a time. The only way to AirPlay audio to multiple speakers is with iTunes on the computer. An iOS device running Apples free Remote app can be handy for this feature.

Let me clarify a little better, you can only play one set of speakers at a time through the ATV whether they are connected or streaming. A work arond to play multiple sets of speakers would be through it's wired connection to a home theater receiver or amp that supports multiple zones. My Onkyo receiver can support 2 "zones" which I don't use since they are wired connections.

I'm not sure if it is different in the UK, but the USA Apple TV allows us to select multiple speakers and choose which speakers we want sound to go to.

partmental is looking to play to 2 sets of speakers at the same time. The ATV lists multiple speakers, but you can only play one set at a time.