Geoff, we all have different comfort levels as far as dealing with our gear goes, but if you own a tube amp that requires biasing, it is best to learn the simple task. As components, and tubes, age, and one's mains voltage varies, it is best to check bias, at least monthly, and adjust it as needed.
It is usually as easy as putting the red probe from your multi-meter into one hole, and the black into another, or touching it to the chassis.
If you are electing to have your tech check the amp and bias it for you, why not just have him give you a ten second lesson in how the biasing is done? Bring your own multi-meter so that he can show you which range to set it on, if it is not auto-ranging. You will be surprised at how easy, and safe, it is, and you will take pride in keeping your gear optimally adjusted for best sound and tube life.