Thank you tkamiya & G-Benz. The drip is coming out from side of the plastic bottle not the bottom box. I don't know much about mechanicals so would appreciate more info:
1. What is a circlip and a circlip pryer? Where can I buy the pryer?
2. I don't have any light coming on so is it possible the coolant level sensor is OK and that it is the O ring or gasket that needs replacement?
Many thanks to you all good people.