You should change the create method and add the logic to load the project template as described in the documentation. After that you just need to use FileBasedProject constructor that accepts the template as a parameter. If you would like to create projects in both ways you just need to add specific logic to decide which way to create the project in the create method.

Brilliant. Have implemented the parser to successfully pull the correct TM file from the template.

However, when running the exe, I now get the error:
The combination of Uri and State properties for the main translation providers should be unique within the list of entries.

This error only appears when I add the ", template" to:
FileBasedProject newProject = new FileBasedProject(this.GetProjectInfo(srcLocale, trgLocale, targetFolder), template);

The template only has one TM listed in the template, but it doesn't have a State attribute:
<MainTranslationProviderItem Uri="sdltm.file:///PATH-TO-TM/TM-FILENAMEsdltm" Enabled="true" />

I then added State="unique", and it processed as expected.
But I cannot see a state setting within Trados TM Settings, so how does this attribute set assigned?

Thanks.

Brilliant. Have implemented the parser to successfully pull the correct TM file from the template.

However, when running the exe, I now get the error:
The combination of Uri and State properties for the main translation providers should be unique within the list of entries.

This error only appears when I add the ", template" to:
FileBasedProject newProject = new FileBasedProject(this.GetProjectInfo(srcLocale, trgLocale, targetFolder), template);

The template only has one TM listed in the template, but it doesn't have a State attribute:
<MainTranslationProviderItem Uri="sdltm.file:///PATH-TO-TM/TM-FILENAMEsdltm" Enabled="true" />

I then added State="unique", and it processed as expected.
But I cannot see a state setting within Trados TM Settings, so how does this attribute set assigned?

Thanks.