Moonloops post (supported by 5 others) was clearly in jest, your response was rude, insulting and uncalled for and, if you value manners as suggested, shows double standards.Churlish ! (you may need to look up the meaning)
Manners maketh man, if you can't say something sensible keep it shut.
Fuel angel is a replacement cap which is orange and has 'Diesel' on it to act as a reminder-----might as well buy Airfix enamel and a sticker (lot less that £40)Which do other members rate as being the best.
or The Rac Fuel Sure
I haven't looked at any of these products. Have you considered something like a Dymo printer? I have one and bought some very 'stand out' tape which appears to stick to anything…………..including filler caps?
Alternatively, a sprung coil key chain with a tag with the relevant fuel type on it, attached on the inside of the fuel filler cover?
... I was just going to write this!Not letting the mrs loose at the pumps! Only joking!