InDesign Having Trouble Importing UTF-8 Data: Greek

I have a website form taking data in character set UTF-8.

That gets imported into a Filemaker Pro database.
The data then gets output using a MERGE format (Data.mer) also in UTF-8.

The MERGE data is read into an InDesign template.

This is working perfectly for ENGLISH data. 
We have a few GREEK data forms which can be perfectly read in the website data and on Filemaker and also in the MERGE data file.

However, all of the GREEK names get completely scrambled in InDesign making these unusable.

Any ideas?

Thank you.