Thanks for all the offers guys, but I have managed to source a heater core.
I have spent a few hours looking through the Mackay rubber catalogue but cannot find anything that will suit for the heater hose that runs from the core to the inlet manifold. A 2L heater hose will do from the heater to the water pump. I am thinking I may need a joiner so I can connect 2 hoses to get the perfect fit.
Summer is coming....maybe I don't really need that heater anyway....
Cheers, Craig.