I have this Eddie Bauer Packable Rainfoil Jacket in 3 colors. I was all set to use one of them on my trip to Ireland (RS tour, July) and Wales last summer. Then I remembered the sideways rain in England and Scotland (May-June 2016) and decided that getting a longer rain jacket (similar to the EB one I had then) would be a better idea. I did and it was.
I took and used the Women's Girl On The Go Trench Coat consistently on my trip. It is not packable, but I was willing to forsake that for the butt coverage. And it was cold and wet enough that I wore it a lot, especially in Ireland.
Both these jackets have hoods. That's a necessity for me. But I've learned that I need to wear a ball cap or a watch cap under the hood to keep it from sliding around and to help keep the rain off my face and glasses. I took both last summer. I used the watch cap when it was cold and the ball cap when it wasn't quite so cold.
BTW, waterproof shoes or boots would probably be good idea, too.
Somehow I've always missed being in the UK in the fall. I hope you experience a beautiful autumn while you're there.