The majority of my trip will be on a cruise ship around Scotland, and some days in a hotel in England. I have a travel-sized CPAP machine which has a heated humidifier, and it takes distilled water only. I read on some other sites that distilled water is hard to find in Britain. If that is true, what do the people there use in their CPAP machines (such as do they use tap water)?
Other forum users have previously suggested contacting your hotel in advance and asking them to provide distilled water. If that's not among their services, they could recommend a nearby drugstore, like Boots. Is that where you would shop at home? I've also seen distilled water in freeway rest stop minimarts in other countries, among the automotive supplies.