Import Bibtex files

Please help. I am currently building a bibliographical database in WordPress using TeachPress. I understand that I can import a Bibtex format file, and as I currently have an Excel spreadsheet with over 2,000 bibliographical records in that I want to import, I have written a VBA macro to generate a multi-record bibtex text file (biblio.txt). So far, for testing purposes, that file only includes 7 records.
When I select that file, using the TP Publication import function, whilst it initially shows me all of the seven titles I want to import into my WordPress file, I can only see the TP Publication entry for the final record in the finished import. Further, if I then return to the Import/Export page and select one of the other titles, again, I can only see the BibTex record of the final entry.
I can, of course, select the individual BibText records from my text file, and paste them individually and then import each one manually, but ideally I want to bulk import the records as a ‘one-off’ process.
Has anyone come across this before, and/or do they have any solution to this?
Thanks for any solution