Forms: Ability to produce invoices to show full date (with month name)

I like my invoices to show the full date with the month written as a word eg 31 October 2016.  I have changed my Short Date settings as suggested in Control Panel to dd-MMMM-yyyy but when I print the invoice it shows it as 31-10-2016.  How can I get my invoice to show the date in full with Day Month and Year (with no dashes) eg 31 October 2016?

"Forms - Invoices"