Dreaded fuel filter location subject (apologies in advance)

Interestingly the fuel pipe was quite loose on the air filter and T thing. It's 5.6mm. The old one which came off measures about 4-5mm. I've put some clamps on there for now until I get some other hose.

 

That looks like original stuff to me, the crimped factory clamp especially. 7mm I/D will do (braided fine for the short bits). You can even use transparent washer hose for the connection from the T-piece: it's what I've got on mine. Cable tie it out of the way. The pipes near the T are only carrying vapour, which should be rapidly sucked away.