I have a Brava 1.8 1996 p reg it only manages about 22mpg aroun d town ,
it appears to run fine ,but the ocasional petrol smell is apperent.
I have checked the fuel system and can find no leaks ,the emisions were fine
for a recent mot. Any info or advise would be appretiated.

check the condition of all sparkplugs, if one looks a different colour, especially black, it shows you have a slight misfire on 1 cylinder, often due to a bad plug or dodgy coil. this can go unnoticed but it wastes fuel and reduces performance.