Order tracking link

The VM has a setting for "Order tracking mode." If it's set to 'none,' there shouldn't be a tracking link in the order confirmation email. It works in VM, but not when VMuikit is installed. Could you please check this setting as well?
Thanks

or, for that matter: how to configure this so that Google Tag Manager can pick up a purchase event to use as a trigger?

I recommend you take a look at www.virtueplanet.com/extensions/vp-conversion-tracking we use that one on several VirtueMart/VMuikit projects.