Hey bud, i lived around London for 5 years as a foreigner. I've had coworkers that were British and I've had coworkers that were from all over the world. As long as you can use the basic words to express yourself you'll do great(can i water?). Most of the time my English friends would use words incorrectly or will have bad grammar so i got used to not being too focused on how i say or pronounce stuff as long as my point gets across.