Attached is photo of warning light that I got this morning almost as soon as I left home. (you can see the temp gauge is not even at half way level yet. 
Additional information:  
1.       Red low coolant light goes on – then after 10-15 mins goes off. 
2.       Water in Radiator seems ok – I top up a bit every 3-4 days – not a lot. 
3.       No water leakage under car. 
4.       New Radiator installed a few months ago. 
5.       New Container next to radiator also installed. 
6.       Temperature gauge always goes from stone cold to mid-way – and stays there. 
7.       This week performance is now not good – some misfiring on start-up and also over certain speeds and under 20 MPH. 
8.       Check engine performance amber warning lit up once – two days ago. 
Any help appreciated as this is getting on my nerves now L