Dont know about the outer Hebrides but if you have horses on an isle you had better make sure of merchants , hay sources , vets etc and their distance from you. I dont have horses anymore but it was a lottery if you could get hay and as for straw, there was no straw on Shetland for a whole year a few years back. Rubber flooring is a solution but hay is an expensive item when it all has to be shipped in, try to get somewhere you can chance making your own if you can but they have protected grasslands on Lewis and Harris so I dont know how they work it. We looked at buying the lighthouse buildings right on the north point ( Butt of Lewis?) before we moved here, such a beautiful place and gorgeous beaches, lucky you!