I reckon the max range is about 350-380 fully loaded on hybrid mode starting with full battery.
I had a Q7 50tdi previously which would go on for 650 miles and the Sorento is nowhere near that. the tank is much smaller (47 litres) but the mpg is better. I get around 45 mpg on a long run according to the trip computer. This does make it look like you should get 450 miles but I have yet to get that. I am driving to Scotland soon which will test the range out.