Welcome drryfly, I spent a full day alone in a beautiful boat on Arrow a few years ago, weather wasn't unlike today, but it was backend.
The fishing was finished really, and I never saw a fish all day, but it is a spectacular place to not catch fish.
I hadn't gone to Ireland to go to Arrow, but I knew of it, and just happened to be passing, so we had a nights B&B locally, and the lady of the house gave me the use of the boat, I had stuck a rod in, just in case mind you.

I shall return one day, hopefully when the mayfly hatch is on, and bag a few of Arrows beauties.
S.