Thank you guys for all of your replies. Yes, as the weather is warming up, my display is showing an increasing average. I'm currently at 43.3 according to the car, but only 40.8 according to Fuelly.com lol.
I decreased my pressure to 30psi to provide a bit of comfort on my 225/35/18's, maybe i need to raise it back up to 34psi . .
Yes, i try to drive smoothly and brake calmly and search for the EV where possible. The MPG is coming up, but I think the Premium is heavier than lower level cars due to the extra kit and features? So i am conscious of that too.
I'm on Nexen tyres all round and they appear to have even wear at the moment. I'm gonna try Haida HD927's when it's time to change. I had these on my IS200 SportCross and would be looking forward to see how they compare on the IS300H.
I have just passed my 60,000 mile service with flying colours, so i shall be picking up a bottle of Forte Advanced Gas Treatment for Petrol Engines to clean out any carbon deposits that may have built up. I am using Supermarket 95Octane. Is there any benefit from trying 97 or 99?