Are the signing fields tied to your test email accounts? That may be the problem. When you replace the test email account with a live email account, you may have to reassign the fields to the live email accounts, because DocuSign just sees that the test email is no longer a signer and will delete their fields. 

If signing fields are getting lost, it sounds like you might be deleting your test bulk recipient and then readding the real bulk recipient.  If this is the case for you, you might consider creating a template, starting an envelope based on that template, and then importing the CSV file in that envelope.  You can test this process out with your test CSV file first.

Thanks both for quick replies! That explains what is happening. Is it possible to create signing fields and custom fields without having them tied to specific signer emails? I guess it must be as thats the point of a template but I cant see wood through trees!

Yes!  In a template, you can specify a role name for a signer (e.g. Buyer) and leave the name & email blank.  Then, when you start an envelope with the template, you fill in the name and email.  This saves you the trouble of having to create/clone envelopes and replace names and emails.

That makes sense! Thanks so much. Much appreciated.

When creating a template, the only thing you need to fill in is the "role" of whoever is signing it. The name and email do not need to be filled in. Those can be done when actually sending the template for signature so that you can reuse the same one multiple times.

Hi again - I'm still not getting this, sorry. So i have started the template from scratch, assigned a role as i did so (I called it "Client") and then saved the template. When I use the template, the role of client is visible, but the only way to attach a bulk list is to add another recipient, and select bulk import, however as no fields are set up for this one I can't test it. Having two recipients is also a little unhelpful as I'm prompted to add a Name / email for the role 'client' whcih will prompt a lot of emails to that address. This alone is not the end of the world if unavoidable, but I'm sure its not meant to work like this... Help is really appreciated thank you.   

OK got it. 'Replace List' is what I needed! Phew.