Ok it works!
I found the issue was the foreign currency.
I had configured a foreign currency (EUR) without using it on any Account.
This caused the Payment screen not to show the payment buttons.
If you change all of the accounts to that configured foreign currency the options Cash and Credit Card will show but not the Customer account option.
Removing the foreign currency with the Accounts settings to default solved my issue.
I now do have to options "Cash", "Credit card" and "Customer Account"
John thanks for your help!
Regards Ruth