I suppose I would fall into the IT professional category, but I'm far too modest to ever refer to myself in those terms.
The FPP isn't dominated by IT professionals as far as I can see. What I have witnessed during the whole process is a wide variety of people from different backgrounds. The only thing it seems dominated by is hard working people who have a real passion for flying for BA. No surprises there though!
Incidentally; I know of two internal applicants who made it. But the backgrounds of the candidates is merely a point of interest; it makes no tangible difference to the outcome in and of itself. For example, the only real advantage to having a degree in engineering is the skills you gained during the degree; not having the degree itself.