Please click the link below:
https://mydvla.dvla.gov.uk/_/staff-handbook/staff-handbook-home/staff-handbook-part-a/chapter-8-a-pay/chapter-8-a-annex-a-allowances-shift-allowance-rra-private-office-on-call-mark-time-engineering-skills
If any links do not work, please contact HRadvice@dft.gov.uk