The colour codes for the std wartime camouflage are all BS381C – just google BS381 Dark Green or Dark Earth and you will get the codes.
You can get solvent borne cellulose mixed at your local body shop supplier. Alternatively you can buy some types direct from LAS aerospace. As mentioned before solvent borne are being phased out in EU and water borne coming in – you can still gets solvent borne but prices are rising.
The alternative codes are RAL – ( R standing for Reich) – which are the german standards that are now more commonly used. There is some cary over from BS381 and you can online search for comparisons.