Only show 'billing addres is same as above' checkbox if there is an address above

Currently you get the 'billing address is same as above 'checkbox if any address profile appears on the screen. However, if only really makes sense to show it if the profile above presents address fields. Otherwise it makes more sense to suppress the box (the form flow of 'billing address is same as below seems wrong )- it would seem incumbant on form builders to put address fields in the top billing box if they want form fillers to be able to fill from above.

I can see a shaky argument for filling from below on a form where users were always logged in so below was always prefilling but on balance I think showing the checkbox only for 'above' forms makes sense.

I guess this could also affect people who have re-organised their tpl to put both profiles above the billing block. Not sure if it makes sense to take that possibility into account