Can I edit my details (date, time, address) once my Catered Order has been placed?

Yes, you can edit your event details after an order has been placed. To edit event details from the 'Orders' section:

Select the order you’d like to update and click the three dots beside the order. Click 'Edit Order'.

You can also reach the 'Edit Order' option by clicking 'View Order'. 

You will then be brought to a new page, where you can edit your order along the right-hand side by clicking 'Change' and make the changes to the details and save. You will need to checkout the order again to save these changes.