Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

Hi, was wondering if anyone can help me out, the wife's corsa arizona has a problem with the washers stalk that I cannot seem to find an answer to.. when i pull the stalk towards me, the wipers activate at front but rear washer activates, and vice versa (push it towards front of car and front washers activate along with rear wiper).
I had a look at stalk in hope that someone had cut and swapped wires but all looks original.
This actually went towards a fail at mot today forgot to mention that it is ass about face!
any pointers please?
all the best Jay

... ok scrub that, it hit me as i submitted... noticed the washer pump has been replaced(white writing on top) so i figd id swatch pipes! et voila! working as it should, serves me right searching for a techy answer all day!