On existing invoices, it would be nice to be able to see the primary contact and their phone number on the invoice screen.
If i'm to look at overdue invoices, click on a particular invoice that needs chasing up, i have to leave the invoice, go to contacts->view contacts, find the contact for the invoice in question and go into it to find the phone number.
This could be streamlined so that i can see the primary contact with their phone number so i can call directly from the invoice screen.
"Contact details on invoice screen"