Hi Paul,
You didn't say what version you were running, but if you are running a version >=12.0, take a look at disabling the Minimal Response option on your WIP. Help documentation says the following:
Minimal Response:
Specifies that the system forms the smallest allowable DNS response to a query. Typically, this is a single resource record in the answer section. When set to disabled, the system attempts to chase CNAME chains, if required, to obtain the ultimate answer, and it attempts to add address resource records to the additional section of the response for each answer when needed. The default is Enabled.
If you try this out, please report back with your results.