Table Ref with Security issue

Hi all,
Not sure if anyone has had a similar issue, tried searching through questions, but can’t see this at all.

I’ve built an app for Leave Requests which is functioning perfectly. However I’ve added security so when the user clicks “Employee” to request leave they only see the users with their email address (hopefully just one entry!)

Unfortunately this means when all the leave requests show, the UNIQUEID() key shows for all other users, and their entry is the only one with the “human readable” name.

I have an “Employee” table with a UNIQUEID() set as the key, and the employees name and photo set as the labels. This is referenced by the “Employee” entry in “Leave” table, with a UNIQUEID() set as the key for each request.
I’ve seen the sample app that pulls the key and copies the associated name here but can’t for the life of me get it to work.

Any suggestions welcome, otherwise I’ll have to remove the security, and slice the data into departments, so they aren’t scrolling through some 100 employees.