I think I might have to roll back and start again, looking at my payment choice on this local server I had Square Payments set up. Thinking this might cause problems (self-cert SSL) I have changed the payment to just Money Order.

Attempting to change the shipping address I get

Code:
[30-Apr-2018 11:35:34 UTC] PHP Fatal error:  1054:Unknown column 'product_is_local_delivery' in 'field list' :: select product_is_local_delivery as check_it from products where products_id='214' limit 1 ==> (as called by) D:\wamp64\www\mydomain.co.uk\includes\classes\shopping_cart.php on line 1679 <== in D:\wamp64\www\mydomain.co.uk\includes\classes\db\mysql\query_factory.php on line 171
never used PDP, but I've temporarily removed that code from tpl_modules_opc_shipping_choices.php and I can now successfully change the shipping address although still no drop-down while having plenty of addresses in the address book.