Thank fook I'm not the only one experiencing this problem
Last night I got home from college and the light was on I went a put £10 in just to take the light off and it went off for about 2 minutes... I did a 30mile blast at a 1er and then went back and put another £5.50 thinking umm that might take the light off... still nothing but it was showing over 1/4 of a tank... me confused by this point as it's closer to half with the light on, knowing sometimes it just takes a while for the needle to catch up after a refuel I gave it the benefit of the doubt.
So I got up and drove college and back today (a fair way but not too far) Still the light is on... So I puts another £10 in tonight and the light still hasn't gone off.. So I've done about 45 miles on £25.50 worth of fuel... and the light has not gone off and the maths don't add up to me...
Nothing I do will make this light go off, and I'm a poor jobless student and can't have anymore money off my parents to fill the tank right up.
I will try and take a look for this cap you mention tomorrow. Any other suggestions would be grately appreciated and do let us know how you got on with yours