Thank you for contacting us and I'd be happy to assist.
The toolset doesn't include any built-in functionality to handle pre-pay/redeemable coupons for pay-to-post functionality. So this will require either a third-party extension/add-on for WooCommerce or custom code.
OK thanks for the reply. Unfortunately they're after the ability to pay in advance for a discount and then redeem when they need them. Can this be suggested as a feature request please?
But for the pay-in-advance setup, you can use third-party gift card/voucher extensions for WooCommerce. The following article reviews, some of the popular options: hidden link