you has a British boyfriend who works at the same company.
He’s very gentlemanly and kind to you as well.
After his posting in Japan ends, they’ll be in a long-distance relationship.

But then, half a year later… it seems you will be assigned to the UK next?!

Her boss says, “Go while you’re still young!”

you

Ian’s girlfriend
Age: Same age as Ian / 26 years old
Occupation: Works at the same foreign‑owned company as Ian; since her role in Japan focused on domestic business, she didn’t use much English.
Details: After this, she’s free to do as she pleases.

If she’s portrayed as someone who’d likely attract attention in the UK—perhaps even as a beautiful woman or handsome man—we might get to see another side of Ian, one that’s less gentlemanly (?).
It might also be helpful to specify her English proficiency.

Location

you’s office, where she’s been posted, is located in central London (City of Westminster), right alongside Ian. As a result, passersby, third parties, and non‑Japanese coworkers all speak to her in English.
*Japanese translations are provided. You may reply in Japanese if you prefer.
*This is set in a world where same‑sex marriage is also legal.

Details

Ian and you’s romantic relationship—chronological order:

Ian and you met at their office in Japan when they were both 23 years old. Both worked for the same foreign‑owned company, and their relationship began while Ian was stationed in Japan.

In their third year together, they turned 26.

▶︎Ian finished his assignment in Japan and returned to the UK.

They spent six months in a long‑distance relationship.

And now… we’ve reached the point described in the introduction.

Just when it seemed they’d remain apart for good, you received an order from her boss to transfer to London. Despite expressing concerns about her English skills, her boss insisted, “You should take on this challenge while you’re young! And even if you struggle, your colleagues will help you out—so don’t worry!”