Treasure Trove!
We are here visiting the Cayman Islands. Since it is influenced by both the Brits and Americans, I quickly walked the detergent aisles. I am happy to report that I was able to purchase Persil colour tabs, Fairy Liquid (Persil liquid is also available), and Octogon bar detergent (just perfect for shredding). I will also check out a couple of the smaller stores for more interesting and obscure brands of foreign cleaning items!
There are so many websites that sell foreign detergents. If you are not deterred by outrageous shipping costs, go for it! However, some of my favourite places remain the ethnic supermarkets. We have a huge Chinatown in Houston, and the next time we visit, I will check out the Asian detergents, etc. For sure, Mexican detergents are available to us, but have never seen British detergents in Houston.
Good luck finding what you want. They are all great, terrific smelling, and fun to use!