Custom QR code/scanning inventory system in PHP (packaged as mobile app)

General information for the website: Custom QR code/scanning inventory system in PHP (packaged as mobile app)
Description of every page/module: We are looking at having an inventory system integrated into a custom PHP based CRM system.

We essentially send out food on a daily basis in our branded cool bags. We need to track these cool bags when they go out to track which customers haven't returned theirs.
Description of requirements/features: Process:

We have some kind of QR code attached to each bag (possibly a sticker)

We then develop an android app (packages web application) we then scan the bag at certain parts during the order and display information in the CRM, stages:

- Scan when sent out for delivery and then scan a customer in our CRM to pair a bag to a customer
- Scan when received at address (with geolocation?)
- Scan when returned back

We'll then know who still has hold of the bag and who hasn't.
Specific technologies required: PHP, QR scanning
Extra notes:

UK BASED ONLY IDEALLY.