Firstly,thanks for your replys,I have fitted a new Coolant Temp sensor as well as the temp gauge one.I have just tried to reset my ECU by disconnecting the battery overnight & doing what the,dare i say it,Haynes manual says & I will be trying the results later today when the engine has cooled down.I will let you know if it was successful.
I also now think that the Air Flow sensor (MASS) could be at fault as when the engine is running & I disconnect the multi-plug the engine runs as normal,no change in revs,if you rev the engine it runs as normal but should this not happen.

Thanks again

Sharky