Considering some of the ‘revelations’ about various types of exploitation on tea plantations, have you considered buying Fairtrade, where there is at least a chance of such being prevented? I buy Co-op Fairtrade teabags, which I think are reasonably cheap, although possibly not the cheapest.
Yes, I know I am a liberal softie with too much money, but I do what I can. At least I am not like a friend’s mother many years ago who would never drink PGTips, even asking in cafes what brand they used, as she didn’t want something that had been touched by chimps.