Well, I have come to the end of my first mini reel of filament and there was just a short length to be removed from the extruder to enable a new reel to be fitted. With the nozzle heated at 200 degrees I could not pull back the filament through the loosened drive at the extrusion motor so I removed the bowden tube at the extruder to enable me to grip the filament and pull it out. It seemed to be stuck firmly in the extruder. Eventually, with quite a bit of force, I did extract it and noted that the end was tapered where it snapped off near the nozzle. Success! Or so I thought. But the new filament would not feed through. Totally disassembled the extruder and ran a drill gently through the middle of it, having first removed the teflon tube at the nozzle end and dislodged a small plug of PLA . Reassembled all and working fine now but I'm sure that is not the process I should have to go through just to change filament. Do you have any thoughts on any flaw in my process?