I am expriencing this right now. The sun is blazing outside. I recently had solar panels fitted. A few days ago I had to have the meter changed from analogue to digital because the old one was moving backwards. My display is showing the word rEd as I speak. I am in th middle of doing some research and came across your question. One can only assume that it is to do with the solar panels. Also the light which normally flashes on the import meter is on solid red until I boil a kettle. This just indicates that you are not using any power from the import meter unless you use power hungry appliances such as a microwave or kettle. When it gets dark it flashes as normal and instead the generating light on my export meter stays solid which means that no solar power is generating. This is normal. As for th rEd display I need to do some searching. Will get back to you as soon as I find an answer x