ΔE 16.6, loose: different enough that you should pick on purpose. Hemp BS4800/10B21 is noticeably lighter, more muted, cooler than Straken Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Hemp BS4800/10B21 is noticeably lighter, more muted, cooler than Straken Green.
The same difference applies the other way round: Straken Green is noticeably darker, 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 Straken Green on the colour wheel See Hemp BS4800/10B21 on the colour wheel
All matches: Straken Green equivalents · Hemp BS4800/10B21 equivalents