I'd recommend Jac Vapour's Vgo2 VV starter kit, a really well made piece of kit and has the benefit of being much slimmer than your current device so it's much more practical for all day use. You get 2 batteries and one Nova style clearo; it's what I mainly use to test all my liquids and recipes as it's a really good all rounder.
The specific model with the larger batteries will run you a little over £50, and you'll probably want to get some extra 2.8 or 3.2 ohm wicks to get the best from it so expect to spend £55-£65 all in. I don't think too much of their e-liquids if I'm honest but their hardware is very good quality.
Hope this helps,
Rob - DarkStar Vapour