Glad to know this! If its possible could you check if the whole base of the UK ones fit the tanks of the FT ones? If mine come and they're not good atleast I'll have some cool coloured tanks to use with my UK heads/bases.
Sorry, misled you.
I used the coil and the base.
You can see the gap through the window between the top of the plastic and the bottom of the internal tube but I've tried tipping it about and nothing dribbles out. Seems to work fine.