A valve assembly comprises: a valve housing comprising an interior cavity having upstream side and a downstream side; and a valve member movable within the valve housing between a closed position in which flow between the upstream side and the downstream side is prevented or substantially prevented and one or more open positions in which flow between the upstream side and the downstream side is enabled. The valve assembly further comprises: a sensor mounting flange on an exterior surface of the valve housing; a first bore in the valve housing linking the upstream side of the valve housing and the sensor mounting flange; and a second bore in the valve housing linking the downstream side of the valve housing and the sensor mounting flange; such that a sensor configured to measure a differential between the upstream side and the downstream side is mountable directly on the valve assembly.