Although I am a secondary school teacher whom nobody wishes to employ (with the exception of my current head who inherited me from the head before her), I wouldn't do this. Firstly, I may worry that you would offend the class teacher. I know I would be suspicious if someone on interview walked into my classroom and regrouped my kids. I'd sit there feeling rather smug as behaviour issues errupted as the interviewee had decided that putting Callum and Tainel together was a good idea just because they are working at the same level. Which leads onto my second point, the seating plan might be arranged like that for a reason. I'm not sure how different it is in primary, and again, my opinion isn't worth much.