Whichever map you pick up, Blaenau Ffestiniog is in the corner, and even then it's often not the bit you wanted.  And it's not just here, there are lots of places similarly tucked away awkwardly or split across two or more maps.  Now all this has changed, for the Ordnance Survey have introduced a customised map service.  Just say which bit you want and they will produce a special map centred on your chosen place.  Both 1:50,000 and 1:25,000 scales are available.