Thanks for writing this up, Cuba. A session of ten 15-minute paired conversations, with a moderator setting the topics, is a format our data doesn't describe. We don't know which platform ran it or whether it was paid, so the people who've done one are the best source. If you're happy to add it, which platform ran it, whether you were paid for the session, and whether anything followed would help the next reader.
The nearest thing in the open roles is the on-site London English project at Sigma AI. Its posting describes annotating, transcribing and recording audio, and asks for a native English speaker, but it doesn't mention paired conversations. For Arabic, the postings describe judging and rating Arabic output and translations, usually remotely, and ask for native or near-native fluency.
If anyone else has sat a live session like this in London, please share how it was run and what came after.