To go from standard gold card to approved electrician you need either the 2391 or both the 2394 and the 2395.
As ECS card information states:
Regrading from Electrician to:
Approved Electrician (Option 1) (Gold Card):
Craft Card Electrician
PLUS current IET Wiring Regulations (Level 3 Award in Requirements for Electrical Installations BS7671: June 2008 (2011))
PLUS Level 3 Award in the Initial Verification and Certification of Electrical Installations AND Level 3 Award in the Periodic Inspection, Testing and Certification of Electrical Installations
Approved Electrician (Option 2) (Gold Card):
Craft Card Electrician
PLUS current IET Wiring Regulations (Level 3 Award in Requirements for Electrical Installations BS7671: June 2008 (2011)) AND Level 3 Certificate in the Certification of Electrical Installations (inspection, testing and certification of electrical installations)