Hi everyone just need a bit of advice currently running a 1.2 Grandland which is better for the engine Esso premium or Shell Premium looking to get most mpg out of it and has anyone experience drop in mpg with using E10? 

It is good that you are considering running on premium fuel as it does have a better calorific value that the E10 fuel which containing 10% Ethanol offers less performance per mile than a better quality higher octane rated fuel.

Since running my older car (but not bikes) on E5 it makes a huge difference on performance and MPG.
Not entirely sure what difference you will notice on a newer model like the Grandland but only one way to find out. 
When it comes to Shell and Esso I imagine they would be of similar quality but again its worth trialling each one to see the outcome