Add user ID to list using flow

Hi All

I have a Sharepoint List with Staff details in. One of the fields is a "person claims" field so I can associate the list data with the Active Directory record.

I have a spreadsheet with the staff details in that I want to transfer to the List. One of the fields in that is the unique logon ID, which looks like "XXX999". This is the ID a user enters when they log into the network each day.

If I manually enter a record in the List and enter the logon ID into the person field, Sharepoint identifies the Active Directory Record. But if I enter it via "Update Item" or "Create Item" in a Flow, the entry fails. 

I have also tried using the logon ID in a "Get User Profile V2" action, but that doesn't work either.

Any advice would be really useful.

I have a few hundred staff records and would rather not enter them by hand 😞