Change Date Format in Customised Form

Hi,

I have created a new invoice template for a specific side of our business, but need to put the due date in.  I've added the "Due Date" field in the invoice template:

But the format of the date is wrong i.e. it displays as "07/05/2024" and I want it to be displayed as "7 May 2024".

Also, the due date itself is wrong even after I amended the customer card to reflect that the bill is due on the 20th of the month following:

Any ideas about how to fix this?

Grateful for any help.