Add another Address Picker to Checkout Process

[Ecompx]

My customers need to provide a collection address during the checkout process so my business can collect garments to wash & dry at our launderette.  How can I add another Address Picker with a drop down menu the same as the existing picker on the Addresses page (step 3 of cart process).  See screen shot.  Is it a case of just copying the code to create another picker & change text to to say Choose a Collection Address'.  If so which file is the code in for Prestashop 1.6.1.4.