//You can go online to obtain a code to give to your hire company. Each code is valid for 21 days from the date you obtain it and it can only be used once (to protect your privacy). You can have up to 15 active check codes at any given time.
To obtain a code or a printout:
1 Go to View Driving Licence.
2 Enter your driver number and postcode, as they appear on your driving licence, and your National Insurance number.
3 Click on the ‘Share your licence information’ tab – then the ‘Create a code’ button.
4 You will now be shown a code that you can pass on to your hire company. You’ll also have the option to print out your licence information.//
https://www.gov.uk/government/news/hiring-a-vehicle
It all changed with the changes in paper driving licence procedures. Anti terrorism measures were one reason. If you rock up with the appropriate code on a printable hard copy, readily available on line you sail through.