Tks Nigel.... I went confident they would know all about rubber impellers for Perkins diesel engines' cooling water circulating pumps, I used the right words ( turbina estandar - from my boating catalogue ) and got the good old curled top lip and shrug of shoulders - they wanted me to want a turbo unit but I don't, honest.  I do want to buy locally but it so often much easier to bite the bullet and pay the postage from UK.  And now for an alternator - I shall try the breakersyard first in Amposta... anyone been there, are they good, bad, average ???