hi essayer,
the code should look like this (this one will not work, don't worry, changed a few characters

):
DEKEFObG5d
It's likely that the DE at the beginning stands for Germany (Deutschland = DE), so probably yours will start with GB. But it should be both characters and digits overall, not GB and then 8 numbers.
Looking at the timestamp of when the email was sent out, it looks to me that it was issued at the moment when the request was sent to Renault's servers, not when the service was finally activated.
As a side note, here's a rough translation from German of part of the email, something that may help you:
====
Activate your services
1. Please log into your My Renault customer area under
Renault Deutschland - Passion for Life (probably renault.co.uk in your case)
2. Select the menu item "My R-Link contracts" from
3. Click on the submenu item "Z.E. contracts"
Within the next 72 hours, the Z.E. be Services enabled on your computer and the contract status changes from "in activation" in "active". Once the contract status is checked, you can proceed with the following steps:
4. Create a user account in
www.services.renault-ze.com Z.E. Customer Portal:
5. Click "Create Account"
6. Fill in the fields (the required Zugangscde see this email)
and click "Preview"
7. Check your entries. Are these correct, click "Submit"
8. To complete the creation of your account, open the confirmation email
"Welcome to My Z.E. ONLINE", you get sent to your specified email address
have and click on the link in this email.
9. Check again your details and click "Submit"
10. Your account has been created.
11. Log on
www.services.renault-ze.com, to access your account.
Now you get all Z.E. specific information to display.
Use also our "Z.E. servces" app for your smartphone.
====
Once you have the My Renault account, do you see the R-Link contracts? You should have the following by default:
1. Z.E. Connect
2. Z.E. Inter@ctive
3. TomTom Live Services
Good luck!