OH! One last thing! Haha if you DO in fact decide to go the Zmax route, I would visit health cabin.net They have some sweet deals on vape gear. Now, keep in mind, they are coming from China, so be sure to order your batteries elsewhere. Shipping is also a little on the pricey side but with the money you are saving on the mod itself, you can't beat it. I'll post some links for ya here in a second. The final think I will say is that I live in Sweden and I got my package in 4 business days with the DHL shipping option. SUPER FAST. With you being in the UK, you should get it even quicker (so they say.) And on top of that, they marked it as "metal tube" so I doesn't throw up any potential flags at customs! Again, I hope this helps. Here are some links. Good luck.
Zmax v5:
http://www.healthcabin.net/index.php?main_page=product_info&cPath=1247_1203&products_id=8485
Zmax v3:
http://www.healthcabin.net/index.php?main_page=product_info&cPath=1247_1203&products_id=8303
Zmax v5:
http://www.healthcabin.net/index.php?main_page=product_info&cPath=1247_1203&products_id=8485
Zmax v3:
http://www.healthcabin.net/index.php?main_page=product_info&cPath=1247_1203&products_id=8303