My 1.6 sport ka has been suffering with an intermittent fuel consumption issue lately where some days I get 50 miles for £10 which is normal and other days barely 33. These and the streetka aren’t the most fuel efficient engines but 20p per mile is acceptable.

i just checked that all HT leads etc were on properly etc then I noticed a pipe coming from the fuel rail sensor I believe wasn’t connected to anything. Should this just be hanging by the ICV to allow air out or should this be connected somewhere? I’ve pictured the pipe in question hoping somebody can tell me what it does and perhaps help with the heavy fuel consumption.

Is 50 miles to a tenner classed as good for a tiny Ka?  Even with a 1.6 engine they can't be that bad?  

I reckon that's a vac pipe from the fuel pressure regulator.  It should be attached somewhere around the throttle body.  As the throttle is opened, more vacuum is pulled which in turn opens the regulator more to allow extra fuel through.  I know access is tight but if you can get a picture of where it connects I'll be able to confirm that.