I noticed something interesting the other day. Many years ago, I made separate Amazon accounts on the .com, .co.uk and .de sites. By chance, I’ve just moved to a new email address, which I updated on the .co.uk site. When I went to the other two to replicate the change, it had already updated.
It might be that any Amazon account can log into and order from any Amazon site now. If that’s the case and your code is giving you grief on your local site, it might work on one of the others. All LT1s are shipping from China at the moment, so the site you use won’t affect shipping time, although it might affect any VAT or sales tax that gets applied.