Well, just to sum it all up...I've got it all up and running perfectly now. (only took me about 3 hours, without hurrying).
Just in case anyone else finds themselves in a similar situation and wants to fix it themselves, I'll tell you what I found out. This relates only to the Mk4 Estate, so I can't comment on the hatchback versions.
Standing behind the car, ready to lift the tailgate, all my directions will relate to you standing in that position. The small washer fluid pipe runs from the wiper motor area to the right hand side, bends and follows the glass upwards and then to the top centre, just behind the hi mount brake light bar. It then goes through one of the two connecting flexible conduits and into the main body of the car...it then tracks to the left (passenger side on the cars you guys drive) and dives down beside LH taillight assembly and into the well behind the wheel arch. At this stage, you will have come across two pipe connectors, not counting the one at the wiper motor end....one is just behind the hi level brake light and the other is just under floor level slightly below the LH tail light assy (that's where my problem was...connector had come apart.) The pipe then goes up and over the wheel arch and from there, I have no idea. I had to remove the upper sections of plastic trim on the tailgate and the upper part of the trim on the body (the large ''u'" shaped one with the VW logo badge on it. Also the LH side trim below the window, and the cubby hole plastic storage box behind it. Hope this is all clear enough.
At the beginning of the exercise, I removed the little black plastic jet from the wiper pivot shaft and left it out for the time being...each time I came across a connector, I applied a bit of gentle air nozzle pressure to clear the line...you would be amazed at what came out! The first time, blowing from the connector behind the Hi brake light, it was like a string of wet spagetti...God knows what the previous owner had been using and no wonder it blocked up!!! When I finally had it all back together and gave it the last test, the jet was reaching my garage ceiling and the pump wasn't making angry sounds...a quick adjustment of the directional ball nozzle (with a fine needle) and all is well with the world again.
Apologies for the long winded explanation, but I'm hoping someone may benefit from it.
