It sounds a great idea Brian - Give IT a burl!
We have 2 Community Theatre reviewers here, on 2 separate local radio stations.
1. is on Curtain University Radio &  number 2. Is on the local Australian Broadcast Commission radio station - both are on a every Saturday morning at different times.
1.  is more like a ?What?s on? type.
2. Gives more in depth reviews of local productions each week.
They work well! {City Population is less than 1 million}
Each theatre group supply?s free comps & get a review or plug dependant on the stations  calendar &/or time slot available.  Also both stations give free plugs over the air - during the week leading up to the show.
I think you would have to work up a demo of a current reviewed production & pitch it to the radio stations?
I hope this helps!

Chookas - Joe

 

In a past life I owned a radio station for ten years.  We were inundated with requests for free air time.  I had a big trash can that I threw it all in.  If I needed something, I reached in to find something.  The issue is more a case of getting your material noticed and used. 

Money talks.  If you can get a sponsor - even if they pay just a fraction of the stations usual rates in return for a "brought to you by _______", the chances of it being used go way up.

Local connection.  Keep it local and recognizable.  Very few people will recognize the name of the leading actors (unless they are known outside the theater) but will recognize that the show is underwritten by "ABC Bank of Hometown."

Work through the big advertisers.  If the media buyers of the stations largest advertisers would like to see more coverage of the theater on the station, the message will get heard.

Relationships are important.  You need to develop a personal contact within the radio station.  Get to know the people there and cultivate them as you would a major donor.

Target your audience.  If your primary audience is senior citizens, don't spend a lot of time on the hard rock stations.  Their high energy formats may not fit the style of your report.

Finally, Time of Day is important.  Work to get your message heard during the prime drive times.  It won't help much if they play your message at 3 am.

G?day Brain
Checked with the 2 that do the broadcasts here - John Flood & Barb Zahari -they both were at the radio stations when the ?In house? idea raised it?s head, to do local theatre reviews & promotion - So I doubt this will help because your on the outside looking in.
Doug with his insider empirical knowledge of ?what?s IT all about!? Will be of fantastic value to you.
One thing these reviewers did impress on me - It is a mine field of ego?s your about to deal with.
As both radio stations are Public Broadcasters, they do not require or need advertisers or sponsors as such. In fact the ABC [Ol? Aunty] is precluded from advertising/Sponsorship by legislation.
However one suggestion was to  initially contact your local rag & see if you can do a regular  ?WHAT?S ON? column for Community Theatre & exspand it to reviews. If you are prepared to do the spade work & give them copy ready to ?put to bed? I'm sure they would jump at it. Also this would be the thin edge of the wedge, in gaining a network of contacts, to pitch your review programme to the Radio Stations.
It?s a shot in the dark - I hope this helps?