Not sure if Humbrol (enamel) paints are available in Europe (or Gibraltar, for that matter!); I've used their satin black paint on a couple of SMC Pentax 67 lenses and really, you would not be able to see the touch-ups! Technique is critically important. An extremely fine, pointed sable-hair brush and thinnest of applications, built up over 6 to 12 hours, is usually more than sufficient. Chips will require filling (fill, then wipe over with your finger to make flush), priming and then painting.