Marcos Maniacs

I'm currently building a Marcos Martina with a 3.9 Rover V8 and have 
obtained a Mantis fuel tank ( which fits perfectly ). My question is 
this : there appears to be a small hose adjacent to the filler hose - 
is this a vent pipe? and what should I do with it as the aero style 
cap I intend using is not vented? 
Also, there is an outlet on the top of the right hand expansion 
tank.  Where should this go ?  

Many thanks for any advice


Andy.