IMHO the NPPL is a waste of time and money, unless done for medical reasons and then it needs to be seen as a dead end anyway.
The standard that's needed for proficient flying around UK airspace will be the same, PPL or NPPL. One may as well go for the PPL. Going abroad is one of the things that makes flying really worth while. Most of the people who stick to flying locally pack it up for good, very fast.