Blitz DC2 gauges

Hi does anyone know how to set these up? Manual online is very brief. Got the boost working fine. It's the oil pressure I can't seem to get going properly. I've recently had my oil pump changed and by doing so it has sorted the annoying whinning sound and fixed the random tapet noises. I have disconnected the Oem sender and fitted the aftermarket one and wired it up correctly to the control box. But my readings are erratic.

From cold the cars oil pressure starts about 2-3 as it warms the creeps up to bout 4 then once at Normal operation temperature the pressure rises above 5 and 6 when driven and drops when idle And sometimes drops to zero. Then while driving again sometimes the reading goes up to 10. I'll be very grateful if anyone can shed any light on this as I've spent hours trying to work out if its normal or wrong!! I can post a video if it would help