You said you only want to buy from U.K. or E.U. You definitely are not going to get a tank over 2ml then. Even if you go outside to U.S. or China finding a vender who will ship something to you over 2ml are slim to none. You are asking for something just not available to U.K customers.
Vape Kits - Creme de Vape
This link may help you, I have ordered from them and they are very dependable and have shipped my orders within 24 hours.
Also consider what wattage you use now and if you will actually use the mod over 50 watts.
I know the TPD2 rules and laws about the max 2ml tank sizes. That is why I ordered a 3.6ml revvo tank for my new mod from fasttech.