Hi Olly,
here’s what i have done :
a minimum order for free delivery and 6 postcodes set. When entering the page with the articles a popup appears with the postcodes in a dropdown menü. After the customers choice of his delivery postcode the amount of minimum order is displayed in the cart. So far so good. But after that i can’t see a possibility to change the postcode for ordering. Because we have some nearly postcodes (i.e. 1210, 1220, 2230, 2231, 2232) it is likely possible take the wrong option.
For now we only offer order by phone in case of some organisational behavior, but in a couple of weeks we will offer also online ordering per mail.
All the best
Reinhard