This is not an unrealistic figure considering that some professions attract trans people more than other professions. Here is the US, there have been surveys of trans women and many have said that they have at one time or another worked in jobs that require a uniform or even carrying a firearm. They were in denial and trying to man up.
The BBC is involved in communications skills and technical skills. It seems that these are two more areas where trans people have talent.
Or maybe 2% is a more realistic figure, since so many of us are in denial or afraid to admit this condition is real even to ourselves.