Had the same situation a few months ago. Can't buy them separate from the whole fuel line, which costs a fair bit. I was lucky in that my local bike wrecker was wrecking a gixxer and had its fuel line to hand, and could see it had the same clip. Bought the whole line (for lot less than new) and just took the clip off and put it on mine (the gixxer line had a right angle in it, so couldn't be used). So.Ö.try a wreckers.
PS I did try automotive fuel injection specialists and car parts places, but all said nah, haven't seen one like that on a carÖ.