Automate stock reduction on Amazon UK when sales made on another site

I have a php-driven (Cubecart) shop and an Amazon.co.uk shop selling books only. ie its a Seller Central account, not a Marketplace one.

I need a script/software which takes an email sales notification and uses the details to reduce stock on Amazon UK. Emails may consist of one order item or any amount up to over 100 but the format is consistent and the book\'s SKU appears on each line and it is the same SKU as on Amazon. ie no database lookup/conversion required.

This script should run on the same server which hosts the shop - currently running PHP Version 5.2.10, MySQL Version: 5.0.81-community and Apache software.

I already have an Amazon AWS account and the access keys but as these are changeable then I would also need to be able to alter them easily.