As I understand it anything purchased airside is permitted to be taken onto the aircraft, unless it is a flight to the USA, when liquids purchased airside cannot be take onboard.
However it would appear that there is some obvious confusion amongst staff about the rapidly changing and considerably varying different regulations from various quarters, so don't take anything for gospel.
Hopefully everything will be a bit more smooth tomorrow after all the staff have got a bit more used to things as they are.