Get a rubber blind grommet kit from Screwfix and plug the hole with one of those. Use a bead of silicon round the rim of the grommet to waterproof it and wipe off the excess when wet. The rest of it which squirts out when you pop the grommet in, can be trimmed off cleanly with a Stanley blade.
______________________
Current:
Not a Citroen!
______________________
Previous:
2017 B9 1.6 BlueHDi Van
2012 B9 1.6 HDi Van
2008 M59 1.6 HDi Van
2003 M59 1.9D Van
Current:
Not a Citroen!
______________________
Previous:
2017 B9 1.6 BlueHDi Van
2012 B9 1.6 HDi Van
2008 M59 1.6 HDi Van
2003 M59 1.9D Van