Your total bill from the CAA will be £348 - with any Examiner Certificate, the highest fee payable is the most expensive applicable Certificate, ie you don't pay for each individual bit. In theory that cost covers their admin time for checking your record, collating paperwork, etc. Pity those who pay £1600+....!
As is now traditional with CAA forms, the SRG1187 referred to on the SRG1128 you're using to apply for reauthorisation has been replaced with a FCS1500. Mmmm, progress...