Posted: 16/03/2017 at 16:40
Did you get started Charles_41? I just love a project!
If you want to preserve the river bank edge from erosion slip you could drive some short pointed logs in, about a foot or two out into river, then back fill behind the upright logs with rolls of coir, rolled turf or barley straw. This 'buffer zone' can be planted with hardy marginals like Iris or Zantedeschia that actually prefer wet feet and tree shade.
It makes an amphibian haven too. I know the Environment Agency uses this method to restore eroded banks and provide habitat. My two plant suggestions are non-invasive and are considered native.