...you can't add variable pitch and retractable gear...
Wrong - you certainly
may add VP and RG qualifications to an NPPL SSEA Class rating!
If tobster911 has done a reasonable amount of gliding, he may well be able to achieve an NPPL in the minimum legal time.
The requirements to upgrade from NPPL to PPL are in LASORS 2010 Section C6.2. Note that the stated hours requirements
include NPPL training and are
not additional - the hours stated are totals.
Those whose budgets are limited may prefer to start with an NPPL as the cost is less, the medical is cheaper and the privileges are adequate for UK day VFR flying. It isn't just a licence for those who cannot hold a JAA Medical Certificate.