Hi Darren,
I had the same quandary a few years ago and I quickly realized that there was little point in doing the NPPL over the PPL unless there was a medical reason for doing so. If you can pass a class 2 medical (or class 1 if you are going commercial) then go straight for the PPL.
Cost wise it will be very similar as you are very unlikely to pass the NPPL in minimum hours, you'd be closer to the PPL minimum anyway at least. Also should you wish to progress to CPL-ATPL later on you'd need to upgrade your NPPL first to PPL then progress onto CPL and so on.
I hope this helps?
Good luck whichever direction you choose.
Cheers,
Dan.