Yep,
Instead of cutting though it seemed to stretch and tear slightly which wasn't what I had in mind for putting through the Filastruder.
I haven't tried a crosscut shredder yet but I'm holding high hopes.
The first one I tried was a "normal" office shredder but I don't think it was a cross cut model.
I've found that shredders go up a class/price point for every security level they do. ie. thin strips/ short length thin strips / "confetti " / grinder / spaghetti pasta maker.
I'll get the make and model details of the one I used so you can avoid that in your search.
Other than that I've used the perforated product from my first experiment (ripped/cut up the lengths) with a hand blender and a fairly thick, tall tuperware container but it seems to turn into particulate matter which is what the MSDS says is the only real problem working with HDPE. (HDPE dust in the air can cause irritation in the lungs)
I have almost resigned to finding the closest plastic recycle station and asking for a kilo of their end product... almost. 