We have studied experimentally and numerically spontaneous transvere pattern formation in a single feedback experiment using an optically addressable liquid crystal light valve in the polarization mode as a nonlinear optical element. Scaling behaviour has been found and transitions between different types of patterns have been observed which can be easily controlled by the bias voltage of the liquid crystal light valve. In a certain range of this control parameter we have investigated the evolution of bright solitary spots showing noncritical slowing down in the switching characteristics. This dynamical behaviour is related to the existence of an unstable branch which separates the basins of attraction of two stable states.