QOS is fine, but hopefully this will stop the crap that Three is currently pulling for roaming. They effectively block (throttle down to bps) Google so you can't use any of their services, search, maps, mail, drive, anything while allowing Bing to operate at full speed.
They do the same with many other services. It used to be fine but my latest trip across 10 European countries showed the same problem in every one, and yet a Vodafone roaming or local sim worked fine. Speedtest was showing high speeds on Three, but try to use many services and it wouldn't let you.