I have a question about the phone app for Givenergy please.

Can someone explain why on my phone app the batteries are charged to 70%, my home is using 600w, the solar is producing 800w but the app is showing that there is still some power coming from the grid.

How much power? It would be normal, as your demand (house load) fluctuates for a small amount to be drawn from the grid to bridge the gap between demand and supply until the inverter has time to adjust drain from battery / charge battery / house supply, but if you have a very steady demand that is less PV + battery, you should see only tiny import / export amounts.

When you say 'some power is coming from the grid' - please be a bit more exact as it makes a difference. Better still post an image of you power flows graph and your inverter settings. We might then be able to reasure you with an explanation.