I Just thought I would put up a few photos showing my first basic extruder, it's working very well and I have used off-the shelf Aluminium 16mm clamps -
You can get these from many places for just a few pounds each (£1.50, $2, 2Euro).
These both hold it to my Repstrap frame and also constrain the PEEK/PTFE hot-end.
It also has the added advantage of cooling the hot-end PEEK, so less of the heat travels up towards the extruder - all good things.
It's just a basic Pinch at the moment, I plan to print a Geared Extruder over the next few days and use the same 16mm Aluminium mounts on that.