Quinie - Thanks for helping. I don't get columbo, sorry. Also not sure that Lewis is right as I already have Lewis as another answer, which is Part of the Outer Hebrides (5).
I see you have just joined AB-welcome. Re no2 I'll have another think.Re Columbo col is a mountain pass-a narrow passage through mountains. As soon as I got col I thought Columbo-googled umbo -it's the boss of a shield. If you google it you'll get the info on it