I drive a DG 1.6 manual petrol (refurb from elite) T25 High-top with body kit (heavy I know) the mixture/timing has been been tested and tuned with a CO2 device too.
I can do 200 motorway miles on average with £50 of fuel @ £1.18p a litre.
My calculations say thats 25p a mile on average which seems pretty high

Not checked my tyre pressure for awhile but unsure if it would contribute greatly.
Could you let me know your MPG, peeps I've spoken to including bays range from 20 to 25 MPG.
Cheers!