I found it very interesting, and I wish I had taped it to watch again. Through most of the programme they were sitting on the fence, going over the book and how it came to be written, and showing things that had echoes in the book. They more or less said that the Victorian view of affection for children was more innocent than in modern times, and an expert on Carroll said there was no breath of complaint about him at the time, though he had a lot of child friends.
Then after the rest of the programme was recorded, they unearthed a photo in a French museum that was labelled on the back as being the older sister of "Alice" and as being by Lewis Carroll. An expert in Victorian photograph examined it and stated that it was done at the right date, and was the same medium and method and style as Carroll, and an expert on matching images matched up the eyebrows, eyes, nose, and mouth to those in a photo known to be the sister.
The damning thing was - it wasn't a child, it was of a young teenage girl with a developing figure, full frontal naked, and looking distinctly unhappy. And they had a letter to "Alice" from the sister, then elderly, which appeared to say that she had been interviewed and had said that the rift was because of his too much affection for Alice, because she had to explain it.
At that time, affection for a small child was looked on as innocent, but with the age of consent at 12, not for a young teenager.