There's two available according to the link below. Decide which one suits your engine and Google the part number to find a supplier, it's as simples as that.
Oh dear, obsolete keeps coming in my search maybe time to make one or have it made by a hydraulic hose firm, DIY bits from these maybe http://fluidpowerservices.co.uk/
Lift pump pressure is relatively low as it is not a "dead head" system and excess fuel is constantly looped back to the tank, just get some fuel compatible hose of the correct ID from a spares supplier and some nice little worm drive hose clips, maybe 2 per end, I think there are many Tdi's getting about with this mod.