ΔE 9.7, close: similar, with a visible difference side by side. Cadre Grey is a little lighter than RAF Dark Camouflage Grey BS381C/629.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Cadre Grey is a little lighter than RAF Dark Camouflage Grey BS381C/629.
The same difference applies the other way round: RAF Dark Camouflage Grey BS381C/629 is a little darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See RAF Dark Camouflage Grey BS381C/629 on the colour wheel See Cadre Grey on the colour wheel
All matches: RAF Dark Camouflage Grey BS381C/629 equivalents · Cadre Grey equivalents