Import not loading CSV data

Having some problems while loading a CSV file containing our project tasks - all of the column names exist but the error suggests they don't or are empty.

An example of the CSV file is:
Item ID,Name,Task Type,Project,External reference,Created Date,last update,Description,Parent task,Status,Closed date,planned start date,real start date,Requested Start Date,planned end date,real end date,Progress,Planning Mode
116,Change Management,Cutover,TestProject,,11/07/2018,11/07/2018 17:23,,GO Live - Support,Logged (No Activity),,01/01/2018,,,22/03/2018,,0,as soon as possible

And the Import result says:

Invalid controls.
the field 'Name' is mandatory
the field 'Task Type' is mandatory
the field 'Project' is mandatory
the field 'Status' is mandatory
the field 'Planning Mode' is mandatory

I've tried and unfortunately it didn't work.

First i tried the example spreadsheet from the Downloads page of this website - it failed
Exported some sample data from our system, changed the values in row 2 and tried to import (this was the CSV data from my previous post) - it also failed.
From the Import page i clicked the ? to show the actual column names, tried those in my CSV file and these also failed.

Tried again and this time used a tiny CSV barebones file containing the DB names and the displayed names (i've made a few changes in the lang.js file, would this cause a problem with the import?)

Some examples of the data i've tried loading are:

Name,TaskType,Project,Status,Planning Mode
Change Management,1,3,1,1

name,idActivityType,idProject,idStatus,idActivityPlanningMode
Change Management,1,3,1,1

These didn't work either - screenshots attached.