To be fair to Isla she's part of the cohort that will have been indoctrinated in trans ideology through school and university. It is unlikely it occurred to her that TW should not be allowed in female changing rooms.
The responsibility here is with the lack of NHS Fife policies leaving the staff to wing it when it comes to trans policies.
Even if they had policies in place the outcome would have been the same I suspect. The only difference would be that NHS Fife would not be able to try and lay the responsibility on a junior member of staff in this way.