go for it......
The people behind the NPPL are adamant that the NPPL does not allow you to fly N reg. However, I impression I get is that the NPPL people are not legally qualified and certainly not experts on the FARs.
I know many people who have flown N reg on NPPL and have been ramp checked. No problem.
This is one of the anomalies of flying N reg. No-one knows all the answers and there are as many opinions about flying N reg IFR with an IMC rating in UK as there people flying N reg aircraft with an IMC. Same applies to the NPPL. Until it is tested in the courts, who knows??
I think you can.
(Head down waiting for the onslaught from the NPPL experts.......)