You don't say what it was, as the usual explanation is that other items are for sale by sellers outside the UK, where different rules apply.
Another reason can be BRAND names, Brand Owners may only allow authorised sellers to sell their item, I suggest you read VERO at bottom of most pages, if this applies.
If there are others for sale in the UK then report them, every item has a report link.
If only you had said what was removed then instead of guesses an accurate answer could be given.
