Which makes it non-compliant in the UK, and no doubt elsewhere too. I don't understand how Apple (hardly a small fly-by-night!) continues to get away with it.

Apple sells a 3-pin extension cable

US Version: https://www.apple.com/shop/product/mw2n3ll/a/power-adapter-e...

If you swap in the extension cable head, that does indeed have a ground pin, at least in Australia anyway. The grounding comes from that metal ring that the connector uses as a guide. https://www.apple.com/au/shop/product/mw2n3x/a/power-adapter...