evellica wrote:We once topped up our bottles from a local farm, but usually we had to get it from streams and boil it.
One of the joys of hiking in Scotland is the abundance of water, you do NOT need to tap-up the farmers. Boiling works but as you have found out it takes time, effort, and of course fuel. There are other options. One option is purification tablets, the army have been using this method for decades but you need to ensure you bring enough tablets and they can leave a taste. Another option is a UV pen but this requires charge.
Probably the most common method is a filter. There are several brands such as Lifestraw, but the most regarded and well-known brand is Sawyer. Have a look at the "Mini" version:
https://www.amazon.co.uk/dp/B00TOX6UM6/That tiny little tube will remove 99.99999 of all bacteria and 99.9999% of all protozoa, well within the margin of safety. The filter is rated to be good for 100,000 gallons of water, for reference you drink about 4,000 gallons in a lifetime. And it's under £25.
You have to clean it once in a while (the instructions explain how, basically you use the included syringe and flush it backwards) and you must never allow it to freeze, that destroys the filter. Otherwise there is no reason it won't last a lifetime.