Ok thanks, I presume there is no simple alternative to this.
Not sure how big a problem this is going to be for the client, it obviously depends on how many customers abort a payment after submitting the checkout page.
Is there a workaround or is it a case of this is the only way the system can function?
So that I can explain to the client can you give some more information about how different payment gateways operate with the extensions.
I'm also curious to know how the checkout page does the database update.