Thanks for the response.
But either I'm not understanding you or it's not quite that.
I've done a diff on the installed components/com_virtuemart/language/en-GB tree & the same tree extracted from the installation zip (VirtueMart2.6.0_Joomla_2.5.19-Stable-Full_Package.zip) and they are identical.
I tried putting a couple of the problem language items in language/overrides/en-GB.override.ini
COM_VIRTUEMART_MAIL_SHOPPER_NAME="Hello %1$s,"
COM_VIRTUEMART_MAIL_SHOPPER_YOUR_ORDER="Your order number: "
But they still don't show correctly.
It seems like just this file , components/com_virtuemart/views/productdetails/tmpl/mail_html_notify.php , is failing to look for the right language items as the other language item in the email, which are referenced from different php files, display correctly.
And I don't understand why the items show correctly when the confirmation email is automatically sent , but if I change the status to shipped and then back to confirmed both the 'shipped' and 'confirmed' emails are wrong.
Edited to addIt was because I had introduced new variable names in base VM 1.1.9
These were stored as "new" fields in VM
Where were the new fields stored ?