Ensure school details are shown only if school details are really known
Ensure school details are shown only if school details are really known

# For schools that have gone missing; i.e. their URN is no longer
# recognised, we show a blank box with a comma in it, rather than allowing
# the user to enter a correct school.

ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app