How to configure a Draytek router to update your dynamic DNS record with Google Domains

1. Choose the "WAN Interface" strategy to use when determining the IP address used when performing updates.
2. In the "Service Provider" field, choose "User Defined". Additional configuration fields appear.
3. In the "Provider Host" field, enter domains.google.com
4. In the "Service API" field, enter /nic/update?myip=###IP###&hostname=your.hostname.here, replacing "your.hostname.here" with the fully qualified name of the record you wish to dynamically update.
5. In the "Auth Type" field, choose "Basic" (this is the default).
6. In the "Connection Type" field, choose "HTTPS".
7. The "Server Response" field can be left blank - I could not fathom from the Dryatek documentation exactly how this field is used. It is possible that a useful value can be entered here in order to prevent the router from performing unnecessary update requests, if anyone can shed light on this please let me know and I will update this guide.
8. In the "Login Name" and "Password" fields, enter the username and password provided by Google. This username and password is unique to the record you are configuring, and can be configured and retrieved from the Google Domains web interface. IT IS NOT THE SAME AS YOUR GOOGLE ACCOUNT CREDENTIALS!
9. Save the configuration. It will take immediate effect.