Ok, so I would be lying if i said that my first reaction wasn't to jump in and cry 'no, no, stop pushing my little boy'. But thankfully i took a breath.
I will bring it up when i go back. I have already asked about his reluctance for me to leave and they said he is fine once i'm gone - but I'm not 100% convinced. He might seem fine to them, but i'd hate it if he was sad. It's only 3 hour hours and it's my only break from him all week, but it's not worth it if he's unhappy.