he we go then my alfa returns an all round average of about 30 mpg and I do not drive slow in comparison my 2.2 mig returns about 24mpg and 3.0mv6 I had returned about 20mpg.
My alfa is 2.0 twinspark sportwagon and performance wise is up there with the mv6 and would leave an omega for dead on a back road unfortunately they are best described as tempremental I think.
Before every one starts slating me for upping an alfa on here please bear in mind with my current 2 migs my total is 6 which has consisted of 2 mv6's, 1 elite,1 2.0cd estate, and my current 2 are a 53 reg 2.2cdx estate and a 2.5cd estate so I am a big fan of omegas.
Somedays I happily drive to work cruising in the omega but most days I do my 70 mile round trip in the alfa not only cause it cheaper but its also more fun.
thats 9.4 lt/100 km..which is nearly the consumption of 2009 model 1.6 liter honda (numerous friends have them) in city traffic , seems your feet stays calm on the accelerator 
to give some idea clit 1.6 sport 970 kg car averages 6.5-7 liters in summer and in winter 8- 8.5 liter/100 km :-/ (city traffic)
I do very little town driving as I live in the country and my journy to work and back consists of 46 miles on the motorway and 22 miles on back roads I also only use 99ron petrol which may or may not make a difference to the consumption.
No offence intended here but if your friend can't get more than 30mpg out of a 1.6 honda he either needs to start using the gearbox or take it back to Honda. I used to own a Civic type R which done better than that on fuel.