Carl, In the end I went old school, although it aint fitted yet (as I over-trimmed my firewall so its too small
- need to make a new one).
I pulled the vacumm thing out the trico washer bottle as i couldtn work out how it was meant to work. I then attached some tube from trico washer bottle to trico plunger button to screen wash jet. Its not the best screen wash action, and you have to push the plunger quite hard, but it seems to work.
HTH
Kevin