I often get a vibe at triage of whether I want to discuss something with a young person on a 1:1 basis without their guardian. I would always be quite upfront but approach the child for their consent to be seen on their own. “Hi Raj, its routine that we can just talk things through together, is it alright if we go and pop into this other room” or “mum do you want to go and grab a coffee or gets some fresh air so that Raj and I can talk things through.”