Hi Rob,
I'm not quite sure what you want but heres how the delivery address works:
In the checkout, in step 2, Address details the user has the option to supply a delivery address :
"Deliver to the billing address" and "Deliver to another address"
If the user chooses "Deliver to another address" another address list is presented for them to fill out.
There are templates in the backoffice for the checkout steps you can look at to see if you can change or add things that you want.
The templates:
"stg2form.template"
"stg2form.xls"
"stg3form.template"
"stg3form.xls"
You can also search the discussions for info about these templates.
I hope this helps,
Geoff