I am not sure the best place to buy AUTHENTIC
batteries in the UK, whether online or local, but there are a few battery types that are gold standards among the
vaping crowd. There are a LOT of fakes out there, so it's incredibly important to ensure that the shop you are buying from is well-reputed.
There are more than just these, but IMO the most reliable batteries you can use for
vaping in 2017 are Samsung 25Rs and 30Qs, LG HG2s and HB6s, and Sony VTC 4s, VTC5s, VTC5As. Again, there a number of other good batteries. Personally, I stick to those seven (and Basen 26650s) and call it a day.