The NPPL minimum is 32 hours, 10 of which are solo. You'll have to be very dedicated to do it in this time.
Has anyone ever done it in this time? The syllabus is largely the same with only a few exceptions, the test standard is exactly the same, so how can anyone realistically do it in less time? I have only ever encountered one PPL student who managed to pass the test after the minimum of 35 hours training (Yes JAA PPL).
The BMAA anounced some statistics a couple of years ago stating the average hours to a PPL(M) was about twice the minimum and not far from the 55 hours often quoted as average for a PPL or NPPL, if you have no previous experience. It takes what it takes to reach the standard, regardless of licence type.