rear wash jets not working???

when i bought my octy vrs the rear wash wipe didnt work , i know its a common problem , anyhow , i fiddled about and found my rear nozzle think was blocked , looked like it had corroded and blocked them , so i cleaned them up put them back on , they lasted for a week before they blocked again .

Acouple of dats later i was driving my vam a merc sprinter and noticed its wiper arm jets look similar , so i pulled one off and fitted to the rear of my octavia and hey presto no more blockage!!