you are prob getting less mpg than me cos yours is a carburettor engine so is inherently less fule friendly, a carb is like spitting randomly into the inlet manifold and hoping the right amount of fuel gets to each cylinder. fuel injection is a controlled amount of fuel, usually sprayed direct into the cylinder, acording to engine conditions at the time so is there fore inherently more efficient.
also your engine works harder than mine because it has to pull around similar weight but with less power to work with therefore more fuel is used
also has your car got 5 gears?
and digifant injection was designed with certain environmental considerations, moreso than your 1.3.
i used to get around 8o miles out of a tenner in my crusty old 1.3.
anither thing to take into accont is the state and condition of your engine, fuel filters, air filters should be clean cos that will lower fuel consumption if they arent.
sorry dont mean to sound preachy! (and im not dissing your car!)