Lister,
From LASORS (Section C2):
"The holder of a UK or JAR PPL(A), CPL(A) or
ATPL(A)* is credited the theoretical knowledge
examinations in Aviation Law & Operational
Procedures, Navigation & Radio Aids, Meteorology
and Human Performance & Limitations and JARFCL
Communications (PPL) if already passed.
(Please note: If no aeroplane rating has been held
in the 10 years preceding application, then the
applicant would be required to pass all the JAR
ground exams."
ie You will need to take the (H) versions of 'Aircraft (General) & Principles of Flight' and 'Flight Performance & Planning'.
"Holders of pilot licences or equivalent privileges for
Aeroplanes (including UK QSP(A)), Microlights
having fixed wings and moveable aerodynamic
control surfaces acting in all three dimensions,
Microlight Helicopters, Gyroplanes, Gliders, Self-
Sustaining Gliders or Self Launching Gliders, may
be credited with 10% of their total flight time as Pilot-in-
Command in such aircraft up to a maximum of
6 hours towards a PPL(H)."
ie the PPL(H) course will be a minimum of 39 hours.
HTH