Last time I looked at it I made 240 miles per tank (45litres)... I looked again and this time I only made just over 200 miles per tank !! I must say it was all short distance city traffic, but still a rather high consumption....
I always have been fastidious (Spelling?) on my fuel consumption in my own Cars. My thinking that if something is wrong I will spot it easier?
From memory I used to get 5.6 mile per litre around town in UK traffic conditions which is roughly what your getting. Short trips under 5 miles and your Fuel Consumption will be higher anything under 2 miles and its going to double. Cold weather is also heavier on Fuel Consumption optimum operating air temperature is 20-25c from memory.
The Manufacturers Figures of what you should get are based on room temperature running in test conditions on a Rolling road. With a unworn engine. Odds of you getting to that figure is remote.
Although saying that I did put a brand new webber Carb on my BX19GT and improved the fuel consumption very noticeably, I suspect it had a engine modification somewhere as it was a ex Hartfordshire Police Traffic Mufty Car
I miss that car