Customer service was excellent, particularly impressed that when the rules changed so that double-vaccinated people only needed one rather than two tests on returning to UK, they immediately got in touch and offered a refund on the package we'd booked and paid for and to replace it with the one-test package. All dealings with them were excellent. 4 stars not 5 because each test contained two sets of instructions, which were slightly different to each other (eg whether to nasal swab one nostril for longer, or both more briefly), and which didn't tally with the actual kit (all the instructions referred to a box to send the test back in, which didn't exist). In the end this clearly didn't matter much for the quality or return of the test, but at the time we didn't know that, and we did know that not having the correct test, properly done and delivered, could mean that we wouldn't be able to leave the country. So it caused a bit of unecessary stress and more than a little bit of swearing.