[John Webb]

I recall Dymo/Esselte make label tapes in, I think, 6, 9 and 12mm widths in a variety of colours. Try Staples or other office supply people, perhaps?
Regards,
John Webb

 

[John Webb]

A further alternative is to print out on paper and then laminate in plastic - gives a lovely smooth and easily cleaned surface. You can used double-sided carpet tape or the like to hold it down to the panel - or rely on the nuts which hold switches to the panel.
Regards,
John Webb