Taking another child abroad

[Teddypops]

We are taking DDs best friend with us on holiday abroad, they are both 12.

Has anyone encountered any problems with this?

Her parents are going to write a letter for us.

I've taken Scout abroad and never had any issues or needed letters for passport control

We got asked about my DDs' cousin when we were coming back into Dover once. Luckily we had a letter from her parents with us. To be fair, she didn't look anything like any of us - was obviously not our child.