Spokes Snapping

I am going through a ridiculous amount of spokes at the rear. Three in about 500k. They break at the elbow. My LBC have been replacing them and trueing the wheel but I get the feeling they are not doing a good job.
Is there a possibility that my wheel is too delicate for the street having previously been only track ridden although clincher. I am running a Campag sherrif star (I am aware of the issues) and Fir EL 20 rims.

That Radio station can't build wheels for shit, better take them to your LBS next time ;)

What is the spoke tension like? If the build is too loose then they flex too much and fail early.
Similar if they are too tight the excess tension snaps them.

Try and compare the tension to a good wheel.