hmm, so i cloned your site here as is , did a COD and a paypal order (using my own paypal credentials of course) and in both cases received the address information just fine.

the only thing I changed was
a) the paypal credentials (and there’s absolutely no reason i can think of that this could be the issue)
b) added the following to the wp-config.php before the /* happy blogging etc */ replacing your current WP_DEBUG etc cnstants

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);/*this should NEVER be true for production sites*/
define('WP_MEMORY_LIMIT', '256M');

Admittedly I would be really surprised if adding those constants to your wp-config.php on your installation would suddenly fix the issue as they are somewhat addressing completely different things.

However, please try adding those to your wp-config.php (most certainly increasing your memory limit would be a good idea in any case) , do a paypal order (sandbox or live) when you get a chance and let me know.
I do NOT actually expect this to fix the issue you are having – I’d be quite surprised in fact if it did – but let’s make sure nevertheless

thanks

(if the above does not make sense to you / is too ‘techie’ , let me know and i’ll explain in more detail)

since i cannot reproduce this here, it’s all kind of guess work , but we can try a couple of things regardless
as laid out below
( especially given that it seemingly works fine with COD orders so my current guess would be it’s a priorities issue somewhat…)

a) in wppizza-delivery-by-postcode.php you will find at approx line 60
add_action( 'plugins_loaded', 'wppizza_dbp_set_version', 11);
change this to
add_action( 'plugins_loaded', 'wppizza_dbp_set_version', 1000);

and save that file

b)in v3x.php at approx line 36 you will find
add_filter('wppizza_filter_formfields', array($this, 'wppizza_dbp_output_formfields'), 10, 2);
change this as well to read
add_filter('wppizza_filter_formfields', array($this, 'wppizza_dbp_output_formfields'), 1000, 2);
and save that file

try doing a paypal order and see if this now gets picked up in it and let me know

(i assume here you are comfortable with editing a few lines of php code , if not let me know)