I thoroughly enjoyed this episode, but then I am aware of both Jack and Micheal Whitehall and how they are together, so wasn't bothered at all by the double act or the glances to camera. I didn't think the researchers were uncomfortable - or at least, no more uncomfortable than they were being filmed in the first place. Jack Whitehall also makes no secret of his privilege.
I'm not sure if I would be counted as a "proper researcher" but I thought the information was presented well, and that their reactions to the diagnosis of syphilis and asylum admission were a surprise and not what they were expecting at all. And I liked the bit where they went through the school corridor! I can imagine what my school would have been like had something like that happened while I was there. Chaos springs to mind.
I also wouldn't put Daniel Radcliffe or Naomie Harris at the bottom of the barrel either - like all 'celebrity', there will be ones which are unknown to a lot of people. Who had heard of Joe Suggs, for example, before he was on Strictly Come Dancing unless they know people who watch him on YouTube? He has millions of subscribers, so does indeed count as a celebrity, as do Jack and Michael Whitehall despite people's dislike of them.