My memory of the figures is hazy, but this is how I recall it...
The NPPL minimum training time is 5 hours less than the PPL, very few people complete the NPPL in less than the time it takes for a PPL. Therefore there is no financial advantage to going for the NPPL.
However, there are advantages (particularly in your situation) to the PPL. You will have a more realistic idea of the budget and any training (as long as it's good training) is useful. If you plan on doing anything more than the NPPL (night, IMC, twin etc.) that suggests that you're willing to pay more to become a better airman. Why skimp on the initial training.
I can see one advantage to the NPPL. The medical requirements. The NPPL allows people who could not obtain a Class 2 medical to fly.