@Alexandre. This is how I've got it setup at the moment. I've tried connecting the lounge via the Deco before the switch but the laptop gets around 30Mbps whereas the switch first it gets around 80...

I'm starting to confuse myself with my setup - hopefully someone can help! I recently upgraded my speed to a 2Gb service - unfortunately my new ISP didn't advise me that my PC might not be able to...