The OP indicated they moved in sometime 2007, so by now (2013) one could expect some degradation of the shakes. Most insurers will either have someone do a visual exterior inspection or have you return a questionnaire at least every few years to asses their risks, which occurred here. No matter who the insurer is this was bound to happen eventually.

My Mom's house was built around 1950 and we've had to upgrade a number of things to please her insurer. Currently they are wanting a rewire or they will raise the premiums but they have not spoken of cancellation. Her insurer has been very good with the few claims she has made so we're not considering anyone else- better the devil you know than the one you don't if the first devil ain't too bad!