For the last few years I have used Harvey maps ....... There may not be mapping for the whole country but all the popular areas are covered.
This is a big minus for many, who don't confine their walking to the "popular" areas - like me!
Picking up on the issue of map cases and plastic bags that cropped up later in the thread, maybe the influence of Blue Planet II could be extended to Harveys - you know, wider coverage = less pollution of the oceans?