Quote Originally Posted by Roodosutaa View Post
I know this sounds obvious but might still be worth checking:

The rubbery stringy thing that your inside fuel cap dangles from when it's undone sometimes gets all twisted up and if it gets caught in between the outside lid and the bodywork/the black plastic liner bit then the lid won't shut properly, hence popping out. I always make sure the rubbery thing goes well inside the cavity before closing the lid.

Oops!! thats exactly what had happened!

Thanks Roodosutaa - You're a legend!