Thanks again all; anyway ordered new sensor . I will check the connector for any damage etc. Presumably the fault could lie in the wiring from sensor to ECU , time will tell. One thing I didnt mention is when the car first started missing the temp gauage swung to max then a second or so later back to normal. No evidence of overheating . Did it a couple of times followed by yellow light which was identified P0335. The breakdown guy said it could be the ECU being confused with signals etc. Who knows?? The light is now out and I will see how long it lasts before I do anything as I will only be driving local.
Update: Just started car yellow warning light on , no rev counter. At least I will know if its the sensor when I replace it.