The extruder head shown in my Previous Post was just a mock up.
My Dad has been busy making me the real parts on his mini lathe at work. Yesterday the parts arrived in the post.
He told me that to make this thing isn’t easy, he broke three 0.5mm drills in the process! The results however are fantastic, thanks for all your time on this Dad.
Giles Bathgate 
What size resistor are you using? Wattage/ohms. From where?
I’ll try the reversed drill too. Thanks
Arvin
The heater design is nophead’s quick heater hack Here is the datasheet. The part can be bought from RS Not sure about a source in the US.