No worries, your replies are timely enough for me, I only get a couple of hours per day at my project so I can just concentrate on other things if I need to.
I have already used the ‘rocks trick’ to hide the join, here is my progress so far on that part of my map.
After playing with the settings for your river, I think I have got a pretty realistic looking stream and mill pond. (I am loving the tessellation when you have a steep angle btw, thumbs up to that)
Regarding exporting the trees and river… the 2nd link you posted is perfect. The first method just seems to export the original mesh you would use to construct the tree. I think I should be able to paint new vertex shaders onto the complete exported spline so no need to do the first method anyway… so far…
The river splines still seem to exhibit the behaviour ‘pre update’ so I think a few of the fixes have failed to migrate.
I am hoping that a reflection issue I have run into also just needs to wait for the update. If I ‘shoot’ an object over the stream, the reflection of the projectile is a bit crazy, also, if I use the First Person Character (with the blue silly gun) the gun gets reflected in the water, way out in front of the character. No worries though, minor tribulations… I can wait. 
Thanks for the new tips.
Dan.
EDIT: I would also echo IceDealer’s comment about the water disappearing under other materials, but only from certain angles. I think this is to do with having transparency on both objects. I have run into this even before I had your pack though, so I am suspecting it’s an engine limitation. FYI: I have just tried using some of the splashes from Epics ‘Effects Cave’ sample but, the splashes don’t render at all in front of the water.
I have read (or maybe heard on your video) that you were possibly going to look at adding a couple of splash effects, did you have any progress on that?