Hi, I previously ordered paint by code and found it very different !
You could either try carmedic for touch ups or I found a place that I brought a piece of car to ( painted bumper spacer ) , they scan and I bought a marker, tub with brush ( like nail varnish ) and a can of aerosol spray ! ( Vinny Byrne, dublin ).
Don't know where you are based but I am sure you should find similar locally with google ?