Your accounts are listed in alphabetical order in the app. If you want to change the order, you can edit the account nickname within the app. Select the account you wish to nickname, then select the 'Edit' icon at the top right of the screen and type the name you wish to use.
Alternatively, you can log on to Online Banking and change the account names by selecting ‘Your details’ in the main menu then 'Change account names'. The order in which they appear in the iPad app will be immediately updated.