Two bags for crew is now a DfT rule.
No doubt this change will take some time to reach the "coalface" and I have no doubt that the power drunk members of the security community will still try to impose the old rule just to fuel there egos.
I will try to find a link to the relivent DfT documents, I would recoment that if you are going to use the two bag rule you have a copy of the net DfT ruling................ I suspect you will need to show it!