The way your post reads suggests that you've had training to conduct an SRA (an instrument approach procedure?) on an NPPL. I didn't know this was possible, indeed my understanding was that with an NPPL you would not even be able to add the 'full' IMC rating (or any other rating) to the licence.
You cannot add an instrument qualification but I can see no reason why you should not practise SRA approaches on an NPPL. It is excellent safety practice and something I did in training for just my basic PPL donkey's years ago never mind my IMC rating. And yes they are good fun and much easier than a raw data ILS