Your pilot will need to submit a Course Completion Certificate (SRG1107) - a gotcha for class ratings is that the Skill Test must be conducted within six months from the start of training iaw FCL.725. Also, he will need a copy of the Examiner's Report (SRG1157) and a copy of his licence when he submits his Application for the Class Rating (SRG3108). Onus is now on the applicant to submit the application paperwork although you should still send a copy of the Examiner's Report to the UK CAA.
Assuming he passes, you will be able to issue a Temporary Certificate (SRG1100). This will allow the pilot to exercise the privileges for eight weeks which, in theory, is sufficient time for their new licence to arrive.
Did you not cover this during your examiner training, refresher seminar or AoC?
ifitaint...