When Minako Aino was Sailor V, she tracked one of the Dark Kingdom's Youma to London. There she met Alan and fell in love with him (though he did not realise this). When she defeated the Youma, she met and made friends with an Interpol officer named Katarina who taught her English. She introduced the two and unbeknownst to her they fell in love. Minako discovered this when she saw them embrace each other, believing she had died. She then decided to return to Japan and leave them alone. This is all referred to in Sailor Venus' Past! Minako's Tragic Love.
Pretty Guardian Sailor Moon
In the live action show, Mamoru Chiba was planning to enter a London university with Hina Kusaka. He did briefly attend even though Hina decided not to, but he returned to Japan before his first year of study was over.