Do you mean the one from the top or from the bottom of the expansion tank ? The top one iirc goes to the tb where as the bottom one goes to a joiner that has 4 or 5 different hoses that go to the rad, thermostat and heater matrix if this is the one your after (and assuming it is the sporting) then I would get down the scrappy as the cheapest I found was nearly 90 quid
Cheers
Lee