Hi "I need to change the address that is sent out on our invoices. These are in the system workflow messages and although I didn't write the code for them, I believe they may have been written in as domain address. How do I update that address please?
As far as I know:
Your default organization address can be found in Administer/Communication/Organization Address and Contact Info. That should be your $domain.address.
You can also update the sytem template Contribution Invoice Receipt and replace the default domain address with your desired address settings if you for whatever reason do not want to update your domain address.