Hose inner/outer diameter

       I need to replace the hose running from the expansion tank to the top of the radiator. Can anyone tell me where the best place to get one is and what diameter I should be asking for if I have to get it.The hose that is on looks original? and is a normal black hose covered in a braided type of material.The car is a1991 cabby with 1.8 engine.Thanks.

VW part is 443121107A @ 14.44 per meter, spec is 7x2.5mm if you want to use aftermarket stuff

Thanks for the information

Replaced mine yesterday, hose plus two clips cost me £3.20 from the local parts place! Shop around