If it's not on here it's not a manufacturer recommended mod. If you get caught out (say after an accident or at MOT time) it could mean that your insurer could declare your cover cancelled and you'd have been driving uninsured.
https://www.vauxhall.co.uk/content/dam/vauxhall/Home/PDFs/owners/owners-manuals/combo/combo-owners-manual-june-2009.pdf
Ffyu, October 2023
