Abstract: A valve assembly comprising a chamber, the chamber having an inlet which is adapted to be connected to a source of relatively high pressure fluid, and an outlet which is adapted to be connected to a source of relatively low pressure fluid, and a switch valve which is switchable between a first configuration in which the valve closes the outlet and opens the inlet, and a second configuration in which the valve closes the inlet and opens the outlet, characterised in that a flow control device is provided between the outlet and the volume of relatively low pressure fluid, the flow control device including a restrictor portion which restricts flow of fluid through the flow control device, the extent to which fluid flow is restricted decreasing as the fluid pressure in the chamber increases.