I was riding for a week in Ireland last month. The saddle I was given had seen much better days and at the end of the second day my seat was sore. Another rider, who had a better saddle, gave me his Cashel seat saver. It literally saved my butt! I was comfortable for the rest of the week.
Since it does rain, stay away from anything that will absorb too much water. The Cashel was perfect. I think it was gel. (At least it felt like gel.). It was made for an English saddle and weighed a bit more than it looked like it should. I am sorry that I can’t provide the exact model, as it wasn’t mine.
Definitely take a seat saver. This was the first riding trip where I actually needed one. Next time I will go prepared.