Why don't you get the DVLA HGV standard med that is reqd for NPPL?
Will cost you about £15 from your GP (you don't even have to go there!)and will see you through solos etc and defer the renewal time for a JAR med.Forms downloadable from
www.nppl.uk.com/
I have done this as I originally intended going for NPPL but have decided on the 'full fat' licence instead.It also lasts until you are 45 years old then is renewed at more regular intervals.
Modelman