Orders prior to plugin install

Thanks for the reply. I am finding that logged in customers and guests who have already made orders prior to using the plugin are getting the discount ? I am having to manually create a mock order using customer email and apply the discount in order to exhaust its use ?

No. Any order that is either In progress, Completed AND LINKED to customer account, should count for those orders. If this is not happening, then you can let us know via our support ticket system.

I have made a mock order as a guest and checked out without using the discount. I then use the same email address to make a new order and it allows the discount ? It appears the discount can be used despite having made a previous order

How do I use the ticket system ?

I have just made a release. There was a release for guest users discount. Can you update plugin and try placing with same guest email?

I have updated plugin. It seems to work if a new account is created as the discount I notice is automatically applied and therefore exhausted for other use. However, since plugin update, I make a new order as guest without using discount, then I make a second order and the discount is still allowed.
Also, the issue with existing customers persists. If a guest customer or logged in customer make a new order, the discount can be used. It seems the code has to be applied at least once to each email address before it is exhausted despite any previous orders