There are plenty though teaching SLMG. So adding an SSEA rating to NPPL is simply differences training with an instructor. But then upgrading to JAR PPL would be difficult.... but who checks who your old FI was. Do the CAA ask for your log book/training record when you attempt to upgrade.
Once we move to EASA FCL, and then opt for the upgrade path, will the same requirement still be in place I wonder.