My University's communications office reserves "Dr" for MDs only - is this common?
The AP style guide does say that "Dr." is used to indicate medical doctor, and that academic degree (Jane Doe, Ph.D.) is used to indicate doctorates. That said, if you don't like that policy, you can point out:

1) It is standard etiquette to use the title a person prefers, and rude to do otherwise.

2) The AP style guide is just one convention among many. Lots of institutions have their own policies (e.g. NASA's communication office has the exact opposite convention, referring to Ph.D.'s as "Dr." and referring to medical doctors as "Jane Doe, M.D."). Several high-profile press institutions (including the New York Times and Wall Street Journal) do not follow the AP style guide in this regard as well.

https://en.wikipedia.org/wiki/Doctor_(title)#United_States