In readiness for a new paint job I have been investigating WW2 era British olive drab (SCC 15). The best answers I have been able to find have been here.

• Vallejo acrylics – equal parts 70924 Russian Uniform WW2 and 70888 Olive Grey
• Tamiya acrylics – 5 parts XF61 (Dark Green) to 2 parts XF62 (Olive Drab) and 2 parts XF3 (Flat Yellow)

It seems a shame that the one ready mixed paint advertised as accurate is enamel. In contrast, US olive drab seems more straightforward.