Litebulbs
You're missing the context. Paragraph 39 begins...
"As to the first limb...."
It is referring purely to the reasonableness of BA acting unilaterally and imposing on the cabin crew because of the failure of BASSA/Unite to negotiate - it is not referring to the wider aspect of the changes themselves, which indeed he goes on to talk about in paragraph 40, which begins "I turn to the second limb: the changes themselves...."
See what I mean?