This answer will explain how to verify your Domain name on 123-reg with Google Apps using the DNS management page of your domain name to create a CNAME record.
Once you have signed up for Google Apps you will be asked to verify the domain name you used to register with. To verify you are the domain owner to Google please follow the instructions below:
Select Change Domain name CNAME record (This will be the domain name you are using) Click on the Continue button.
You will then be taken to a page with the CNAME settings.
In the Domain names section, select the relevant domain name in the drop-down list and click on the Manage button.
Click on the Manage DNS link.
You will now see the DNS management screen. Scroll down to the A, CNAME and Mx records section.
Enter the CNAMES record provided by Google Apps in the fields below Add new entry
Click on the Update DNS button to save your changes
Please note: It will take between 24 - 48 hours for the new DNS records to become active.