Got an email from Zen this morning at 08:51 with some details and info on how to request my account be enabled. I sent an email requesting enablement a few minutes later and Zen had set it all up by 09:10.
Tip to anyone else still waiting - reply to the email you got this morning - was then set up in minutes. (originally i composed a new email to the address in the email)
So long as you have emailed the trial email address, it does not matter whether you replied to this mornings email, or created a fresh email. We will aim to enable accounts within 48 hours. We'll be processing them occasionally throughout the day, but the majority of updates will be performed first thing in the working day.