1. What version of Zen Cart ? Was it an upgrade? From what version?
v1.3.7 [2007-02-24 01:53:55] (Fresh Installation)

2. What addons/contributions do you have installed?
many, including... ask a question, contact us (add subject), direct bank deposit, edit orders 1.1, e-mail adress exporter, off-site payment, pop-up on attribute images, printable pricelist, quanitity discounts, stock by attributes 4.4, store credit module, time zone offset, user tracking, un wishlist 0.31 & added 2 blank sideboxes.

3. What are all your settings in Admin->Configuration->Email Options?
Title Value Action
E-Mail Transport Method PHP
E-Mail Linefeeds LF
Use MIME HTML When Sending Emails true
Send E-Mails true
Verify E-Mail Addresses Through DNS false
Email Archiving Active? true
E-Mail Friendly-Errors true
Email Address (Displayed to Contact you) enquiries AT ajms DOT co DOT nz
Email Address (sent FROM) enquiries AT ajms DOT co DOT nz
Emails must send from known domain? No
Email Admin Format? TEXT
Send Copy of Order Confirmation Emails To ange AT ajms DOT co DOT nz
Send Copy of Create Account Emails To - Status 1
Send Copy of Create Account Emails To ange AT ajms DOT co DOT nz
Send Copy of Tell a Friend Emails To - Status 1
Send Copy of Tell a Friend Emails To ange AT ajms DOT co DOT nz
Send Copy of Customer GV Send Emails To - Status 1
Send Copy of Customer GV Send Emails To ange AT ajms DOT co DOT nz
Send Copy of Admin GV Mail Emails To - Status 1
Send Copy of Customer Admin GV Mail Emails To ange AT ajms DOT co DOT nz
Send Copy of Admin Discount Coupon Mail Emails To - Status 1
Send Copy of Customer Admin Discount Coupon Mail Emails To ange AT ajms DOT co DOT nz
Send Copy of Admin Orders Status Emails To - Status 1
Send Copy of Admin Orders Status Emails To ange AT ajms DOT co DOT nz
Send Notice of Pending Reviews Emails To - Status 1
Send Notice of Pending Reviews Emails To ange AT ajms DOT co DOT nz
Set "Contact Us" Email Dropdown List <enquiries AT ajms DOT co DOT nz>, Enquiries about products <ange AT ajms DOT co DOT nz>, Contact Ange (Owner) <admin AT ajms DOT co DOT nz>, Enquiries/suggestions about the site <sales AT ajms DOT co DOT nz>, Request a new product
Allow Guest To Tell A Friend true
Contact Us - Show Store Name and Address 1
Send Low Stock Emails 1
Send Low Stock Emails To admin AT ajms DOT co DOT nz
Display "Newsletter Unsubscribe" Link? true
Audience-Select Count Display true
SMTP Email Account Mailbox ange AT ajms DOT co DOT nz
SMTP Email Account Password ******
SMTP Email Mail Host ******
SMTP Email Mail Server Port 25
Convert currencies for Text emails &pound;,&#163;:&euro;,€

4. Do all *other* emails go out fine ?
Yes

5. Does this affect *all* order-status-update emails, or just to certain email addresses?
All order status update e-mails. They recieve the confirmation e-mail but no updates. I receive the updates through admin e-mail but customers do not.

Thankyou for your help.
Ange