Thanks all - will probably either take it out, or email them. I got it in 2009, so 4 years old, just thinking of a slightly longer post, because I think the stock one doesn't extend that far before the markers.
He'll soon need a new bike, but that's the beauty of Islabikes, and the first bike I got for my kids (Ridgeback MX-14) decent enough, that they'll do for at least 2 kids growing up, probably more.