Apparently there is atill a mystery about what causes phenomena like this and the Azores/Bermuda High.
Well there is, it's a mystery to me why they won't accept was is bloody obvious. But who is going to listen to me? …
In settled weather, when it obeys the weather lore for the month, you will always find an area of low pressure just off Iceland.
Since it is about 15 degrees of arc from the Irish Sea, it means fine weather is the norm. This is what it looks like: http://www.woksat.info/etcra16/ra16-1308-c-uk-n.html
THe parallels or latutude lines shown are 65 N. through Iceland, 60 north of Sotland and 55 through Northern Ireland and Carlisle on the Anglo/Scots border.