BBC Worldwide content is available free to worldwide audiences, funded by advertising; therefore it follows that BBC license payers back in the UK must not be allowed to access this ad-funded content because they haven't "paid" to see it by being subjected to adverts.
As the BBC help page I was redirected to after being sent this story by a friend overseas states:
"We're sorry but this site is not accessible from the UK as it is part of our international service and is not funded by the licence fee. It is run commercially by BBC Worldwide, a wholly-owned subsidiary of the BBC, the profits made from it go back to BBC programme-makers to help fund great new BBC programmes. "Yes, it makes perfect sense. If UK license-fee payers were allowed to see this content for free then Great Programmes wouldn't be made and the world would end.
No mention of the complex cross-funding deals that allow BBC Worldwide to sell license-fee funded programmes whilst returning a meagre 10% of its turnover to the Beeb Proper, or the £687,333 redundancy payment made to a BBC executive leaving the BBC to join... BBC Worldwide, its wholly-owned subsidiary.