Looks to me like someone has copied and pasted the names provided to them onto the information. Not everyone is an instant expert on rank titles, and if they get a covering note saying 'photo X is Flt Sgt Bloggs' then they will usually run with it.
In times like this why not just do what I've done in the past and send a quick and polite email to say 'there is a mistake' and they will usually fix it very quickly. The
PR people are in my experience good people who are keen to do the best they can to support HM Forces, and appreciate it when people point out mistakes so that they can fix them. Really not worth getting wound up about in my book.