Yes, brick slips are heat resistant.
When our bricks were originally made back in the day, they would have been fired in a kiln at heats over 1000 degrees celsius, so they are more than capable of handling the heat from a domestic log burner, wood burning stove, gas or electric fire.
Our brick slip adhesive and pointing mortar have both been specially selected by us, due to them being heat rated and suitable for use around heat sources.