The two articles (BBC and Mail) seem to get things wrong in opposite directions. The BBC allows us to be misled into thinking the arrested person is a woman, and the Mail begins by screaming 'trans' in the headline and the first sentence.
It is reasonable to expect new stories to inform us about sex. (Surely sex is more relevant than the fact that he is 50 years old! And if we were routinely ignorant of the sex of the subject of a crime report story, we would not be able to form perfectly sound and useful generalisations about relative offending rates of men and women).
But it isn't reasonable for a story to centre trans identity in stories that don't contain or imply any reason for thinking that being trans is relevant to the alleged crime. In fact, it is probably discriminatory on the part of the Mail.
I think the best solution is to avoid pronouns, and to add a clause to some low-profile sentence saying something like " ..., who is transgender, ..." if there is a risk that the reader would otherwise be misled.
Some people might say: There are quite a few names that don't signify sex, as well as readers who may be unaware of the 'sex of a name' if they are from a different heritage from the subject of the story. Why do we only have to clarify sex where the person is transgender and has a name that is associated with the opposite sex?
But in cases where a name is sex-neutral, or doesn't signify a sex to a reader because of different cultural traditions, there will almost always be one or more pronouns in the story that clarify sex. It is only the scrupulous pronoun avoidance (or wrong pronoun use) that causes difficulty.