2001 Alhambra 20VT windscreen wipers have been fine. Recently had a service & they changed the pollen filter. hadn't used the wipers for a while & when switched on seemed OK but would not park properly. Intermittent wipe is chaotic they move about 30 degrees & stop then jerk in small steps across as the screen delay kicks working but as park isn't they just stop. try to park them but either stop at about 30 degs or upright! Seems that when the garage changed the pollen filter they have done something to the wiring of the park circuit. broken wire maybe? wiring on these vehicles is notoriously brittle. Motor is fine & spindles not seized as they run fine in normal operation. Any other thoughts?