Where do you find out what GCSE papers are on offer?
Dd's school only offers French as a modern language, but have hinted in the past that they would be happy to let her sit a Swedish GCSE (she is bilingual and we would organise tutoring if she needed it). But can you do Swedish GCSE these days? Where do you find out?
Dd is also rather keen on doing German, which again is not on offer at her school- but I assume it could be organised somehow? Again, we would arrange tutoring.
btw I see nothing daunting in doing 3 language GCSEs; I think dd would be fine.