Hello there, @Izzy81.
 

To successfully import your bank transactions, your CSV file must be formatted correctly. To work out this process, let’s double check first the format of the file.
 

Here are some formatting restrictions for CSV files:

• Special characters are not allowed.
• Remove zeros (0).
• Correct any transactions that display a number in the Description column.
• Remove the word amount if it appears in the name of the Credit or Debit column.
• MAC users must save the file as a Windows CSV file.
• Correct and standard Date format to a single format (for example, dd/mm/yyyy).
• Some banks provide the day of the week and include it in the Date column (for example, 20/11/2018 TUE), which is not an acceptable format. To correct this, split the date and the day of the week into two separate columns.

Here’s how to import transactions from a CSV file successfully:

1. Go to the Banking menu and select Banking.
2. Select File upload.
3. Select Browse and choose the file you downloaded from your bank then click Next.
4. Select the appropriate bank or credit card account then select Next.
5. Map the statement fields according to your CSV file format and select Next.
6. Select the checkboxes of the transactions to import and select Next.
7. When prompted to import now, select Yes.
8. Select Let’s go! when the Import completed notification appears.
    

Once the import is finished, you can go to the Banking page where your imported transactions are displayed on the For Review tab. You can review, add, or match each transaction.
 

You can check this article for further details: Import bank transactions using Excel CSV files.
 

You can always leave a comment in this page. Keep in touch if there's anything else I can help you with. Have a great day!