UK missing from shipping list

Hi

When I checkout from my product page, some of my items include the UK on the list of shipping options- eg this one https://longcroft.net/products-page/gicleeprints/the-monochrome-set/

But others don’t, including my latest one. https://longcroft.net/products-page/prints/southwick-poster/

On the ones which do, I get a red notification “Some of your cart items are targeted specifically to certain markets. As a result, you can only select those countries as your shipping destination.”

So I presume I must have applied some particular instruction on those ones, which I can now neither find nor remember.
Would anybody know what that might have been? Or why the UK would be left out of the shipping list?

Thanks!

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