Jane Austen Collection: Emma/Mansfield Park/Northanger Abbey/The Biography Book

John Lahr has the first and last word on Joe Orton, and it doesn't feel right. I've read his foreword to Orton's diary, his foreword to Orton's collected works and this, his Orton biography. I'm thinking:
1) Lahr's narrative is so powerful that when Lahr interviews people for a BBC documentary (youtube), they tell the same anecdotes back at him as he set them down in the biography. I'm suspicious. Doesn't anyone have a different take? Lahr seems to avoid a "this is my assessment of Joe Orton" approach and goes for "This Is Joe Orton. Nailed." And there are elements that must be controversial: we do not know that Joe planned to leave Kenneth.
2) I think that Lahr finds it really hard to forget that Kenneth kills Joe at the end. He has something of the approach of a Whig historian; everything in Joe's life signposts to the murder at the end. Really? Is this how our lives work?
3) This is a literary biography; Lahr is looking for Orton in his plays. But Orton isn't Shakespeare; he wrote three full length plays and, crucially, many of the people Orton met are still alive. It would be possible to talk to them. I felt that I wanted more of this. What was Orton like in prison? Surely there are records of the prisoners and prison officers he would have known. Did they have anything interesting to say?