That's probably due to the verdict issued by UK court.

Craig Wright claimed that he is the creator of bitcoin and owns copyright to Bitcoin white paper. He filed a lawsuit against Cøbra (Bitcoin.org domain administrator) and won that. UK court ordered Cøbra to remove the bitcoin whitepaper from bitcoin.org.
Most probably, bitcoin core isn't available for download in UK for the same reason.


For more information about the UK court order, visit the link below.
UK Court Orders Bitcoin.org to Remove White Paper Following Craig Wright Lawsuit

On a side note, Craig Wright won the lawsuit, not because he proved his claim. He won the lawsuit because Cøbra didn't want to reveal his/her identity and didn't appear in the court. We all know that Craig Wright isn't Satoshi.