When the WRNS were fully integrated into the RN in 1993, they gave up their original WRNS rank and associated insignia (Third Officer with one blue ring with a diamond-shaped curl, in Jo's case) and became the RN equivalent (Sub-Lieutenant with one gold ring with circular curl).
As for her inclusion in the `89 team phots. I guess the team felt (and I wouldn't disagree) she did more to enhance the image of the team than previous , or subsequent Staff Officer's of 705 Sqn who provided admin support
. Let's face it, looking at that team phot, their image was in serious need of some sort of enhancement.