Hi Andy,
I think what you have found just exports what you see on your screen - really what you would need to move data over is the Client_Ledger.csv from the account backup.
There is a guide on how to create back-ups here: Create a data backup schedule
If it is easier for you then we can copy over your suppliers/clients for you. We will just need to know the original account number and the account you wish to copy the information to.