I would think your best bet is Ebay. There are a LOT to choose from there, mostly out of China and quite inexpensive. Shipping may take a couple weeks but guessing you wont be hitting the beach in GB anytime soon. Be sure to check the details because China sizing is much different than the rest of the world. check the inches or centimeters before you buy!
I have been a bit of a quandary about appearances. I don't care about tan-through, I don't tan anyway and rarely lay in the sun. I have been wearing Speedo-type suits from N2N and other brands for my exercise swimming at the Y and other health clubs. They're clearly the best for moving through the water, and they dry quickly. But then I read comments here from guys who are concerned about "too much showing" and not having "a Speedo body," which leaves my wondering if I should rethink my boundaries. I'm legal, and the lifeguards are generally friendly. I guess it's just a personal preference.
I guess that I am too old now to care about appearances, though I never was much on keeping to current fashion trends. At the pool or on the beach or bike path, I wear sports style no fly boxer briefs or spandex exercise shorts. Both types are light weight, dry quickly, and allow for a bit of breeze to pass through. The material is thin, and they hug me closely. Any one seeing me can certainly know I have genitals, but I have never had anyone object to what I was wearing. So get more comfortable with your choices. People may see you, but most really don't care, and unless they know you they'll only be looking as some stranger that they are not likely to see again.
I swim in pools a lot as training for ocean swimming. Always wear speedo type briefs, the briefer the better these days. I like the old nylon style as you feel naked pretty much but the chlorine destroys them relatively fast so you need to replace them.
When I go to non CO beaches I use the cool tan shorts to try to get some colour but it is limited. Otherwise I use the speedo briefs and wear them as much as possible.
When I swim at the gym its always a brief usually a 1 speedo solar or Sporti euro brief from swimoutlet. I usually the only guy in a brief. At the beach if thongs are legal then its a thong. If not I wear a string bikini suit by n2n. I wear the least possible depending on the environment.