I had this a while back... Check the ends of the rubber fuel pipes from the Fuel Rail down to the main Fuel lines...

Mine was leaking at the top side of the pipe where it connects on to the fuel rail (Bulkhead side) and where it connects to the very small filter type connection on the main lines, which are right at the bottom of the bay on passenger side in between the block and inner wing..

just follow the piping and you will find them ... he he

Mine were not Jubilee clipped and dont think they were from factory as they are heated on... so could just be coming loose after time, i jubilee clipped all ends and now fine.