I just went to visit some puppies, was told the mother is a lakeland/border cross and the father a border.  One of the puppies had a lot of white on him - is this possible?

do you mean white was the main colour like a jack russell or just a big white patch on the chest? the latter is feasible with border lakelands.....they are a populare working cross and I get to see them often....but white as the MAIN colour suggests someones telling you porkies!!!