My "take" on this, at the time, was that I saw no reason why diabetes.co.uk should not charge for this programme. It is not a charity or a government department, to my knowledge. As someone who has designed websites and written software, I know how much time and expertise can go into such things.
What I did see evidence of, was that the "rollout" of this charge was clumsy. Among other things, people signing up to the programme apparently were not told about the charge until they were already some way through the sign-up process. Also, even after the introduction of the charge, the programme was still referred to as "free" in other parts of the website.
(The info in that last paragraph is second-hand and based on what others said, in the earlier thread.)
There is no way of knowing of the charge for the low-carb programme until the sign-up form has been filled in.
There is still no indication of a charge on any of the webpages.
I personally dont mind them charging, its their site to do what they want with. I do object to there being no indication of the charge until the sign up has been completed.