Het antwoord voor dit probleem heb ik intussen gevonden.

Full steps if you need them:

1. To get to the right area you choose : >>Dashboard Menu, then choose the problem >>Bank account
2. Heading 1 will show "Accounting Dashboard / Bank Reconciliation " if you're on the right page
3. Now choose the List view, for convenience
4. Change the range from the default "1-80" if you wish to something like "1-9999", again for convenience
5. Then, click the "Select All" button
6. Lastly choose the "Action" button and then the "Delete" function

And they're gone!

7. Optional Step (to delete unwanted bank accounts) - Choose "Configuration menu" from top menu, Select any unwanted bank accounts, then choose "Delete".

Thanks to a post of Mark Philips