Okay all of my plans for checking fuel efficiency and ways to improve this for both petrol and diesels have now been wrecked.
We have sadly been having a major over heating issue with the car for a month or so now and it has finally been diagnosed, the main engine block is cracked causing air to get in, to much air!
Obviously it would be simple enough to just replace the engine but in the long run we feel it would be just a bit to expansive for us to do this and well when we can survive with just one car what is the point in having them both. Its a case of paying twice for absolutely everything, tax, insurance etc.
So my tests will be done on diesel. Which in fact seems to be the fuel no one helps as it is already pretty good. But with it being in some places 20p more than petrol per litre every single mile you get from a gallon counts!!
I will attempt tests for petrol with any friends cars who I can tempt but as for now i make no promises.
Just thought I would keep you updated. At the moment I am reading into a chemical which you can add to fuel to increase mileage.
However not sure if it works with diesel yet so I will keep you all posted.