Zip ties don't work on aluminum fenders, or at least won't last - the aluminum will cut through them at some point. Here's how to attach the fenders without using any bolts at the rear. Put the strut approximately where you would put it if you were using a bolt, then wrap the zip tie between bolt hole and dropout window. The hex wrench is for tightening the bolts that hold the struts in position. Heron with complete fender installation.
Zip tie on front eyelet.
Here's a better view of how it all goes together. The Heron Touring has a generous amount of room here for the fender. How to attach the front fender at the fork crown. There are two holes in the fender under the crown there.