I never buy mod kits. I just assumed you were fixed on the kit you linked to. Kits often include things you don't need or inferior essentials (like that battery charger). I didn't see any cartotanks worth recommending from the UK website, and I'm not familiar with the European venders to suggest where to find any.
Provari List
Provari Mini
Battery Extension Cap (for 18490 battery)
Batteries AW 18350 IMR 700mah - 3 batteries
Batteries AW 18490 IMR 1100mah - 2 batteries
Battery Charger - Xtar (your choice; whichever can charge 18350 batteries)
Innokin
iClear 30 clearomizers - 3 clearos