ΔE 12.7, fair: the same colour family, but not a straight swap. Military Yellow is much more saturated than British Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Military Yellow is much more saturated than British Brown.
The same difference applies the other way round: British Brown is much more muted.
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 Brown on the colour wheel See Military Yellow on the colour wheel
All matches: British Brown equivalents · Military Yellow equivalents