We generally recommend entering your own address as Etsy's listing system only allows one delivery origin address per listing, while Prodigi offers the flexibility to manufacture from different locations (UK, US, Netherlands) based on the customer's location.
However, if needed you can use on of our addresses detailed here-
Alton
Unit 20
Caker Stream Road
Alton
Hampshire
GU34 2QA
UK
Charlotte
6509 Northpark Blvd Suite #100
Charlotte
NC 28216
USA
Venlo
Jan van Riebeeckweg 15,
Venlo
5928 LG
Netherlands
One way to get around the single origin address issue on etsy would be to make separate listings for each major market (US/UK) so each listing would have the correct local POD facility address and you can set up shipping profiles specific to each region
Alternatively, you could set it up based on your primary market (e.g., UK) in which case you list with the UK facility address and then add clear notes in the listing description about variable production locations
Please ensure your shipping profiles account for international shipping times