ΔE 8.3, close: similar, with a visible difference side by side. Grey Brown is a little darker, more muted, cooler than British Khaki.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Grey Brown is a little darker, more muted, cooler than British Khaki.
The same difference applies the other way round: British Khaki is a little lighter, more saturated, warmer.
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 British Khaki on the colour wheel See Grey Brown on the colour wheel
All matches: British Khaki equivalents · Grey Brown equivalents