Filament is jamming in the Bowden coupler on top of the heatsink - probably have to drill it out. 

Managed to finish threading the XY cords and tensioning them.  Now to see if I have the motors the right way round and rotating in the right direction - three things to get wrong

Now to analyse the results...  X+10 moves Y -10 and X+10.  Y+10 moves Y +10 and X -10.  Conclusion - CoreXY not enabled.

Needs

M667 S1 ; switch to CoreXY mode

Strange - it's already in there

; Configuration file for Duet WiFi (firmware version 1.20 or newer)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Wed Jan 31 2018 19:48:21 GMT+0000 (GMT)

; General preferences
M111 S0                                  ; Debugging off
G21                                      ; Work in millimetres
G90                                      ; Send absolute coordinates...
M83                                      ; ...but relative extruder moves
M555 P1                                  ; Set firmware compatibility to look like RepRapFirmare
; Automatic saving after power loss is not enabled

M667 S1                                  ; Select CoreXY mode
M208 X0 Y0 Z0 S1                         ; Set axis minima
M208 X400 Y400 Z800 S0                   ; Set axis maxima

; Endstops
M574 X1 Y1 Z1 S0                         ; Set active high endstops
M558 P4 H10 F120 T6000 I1                ; Set Z probe type to unmodulated and the dive height + speeds
G31 P500 X20 Y0 Z2.5                     ; Set Z probe trigger value, offset and trigger height
M557 X15:385 Y15:385 S125                ; Define mesh grid

; Drives
M569 P0 S1                               ; Drive 0 goes forwards
M569 P1 S1                               ; Drive 1 goes forwards
M569 P2 S1                               ; Drive 2 goes forwards
M569 P3 S1                               ; Drive 3 goes forwards
M350 X16 Y16 Z16 E16 I1                  ; Configure microstepping with interpolation
M92 X50.93 Y50.93 Z763.95 E418.5         ; Set steps per mm
M566 X900 Y900 Z12 E120                  ; Set maximum instantaneous speed changes (mm/min)
M203 X6000 Y6000 Z3000 E1200             ; Set maximum speeds (mm/min)
M201 X500 Y500 Z250 E250                 ; Set accelerations (mm/s^2)
M906 X800 Y800 Z800 E1500 I30             ; Set motor currents (mA) and motor idle factor in per cent
M84 S30                                  ; Set idle timeout

; Heaters
M305 P0 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 0
M143 H0 S120                             ; Set temperature limit for heater 0 to 120C
M305 P1 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
M143 H1 S301                             ; Set temperature limit for heater 1 to 300C

; Tools
M563 P0 D0 H1                            ; Define tool 0
G10 P0 X0 Y0 Z0                          ; Set tool 0 axis offsets
G10 P0 R0 S0                             ; Set initial tool 0 active and standby temperatures to 0C

; Network
M550 PGinaRep Giant                      ; Set machine name
M552 S1                                  ; Enable network
M587 S"Ubiquity" P"5a3853a2a4"           ; Configure access point. You can delete this line once connected
M586 P0 S1                               ; Enable HTTP
M586 P1 S0                               ; Disable FTP
M586 P2 S0                               ; Disable Telnet

; Fans
M106 P0 S0.3 I0 F500 H-1                 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H1 T45                ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H1 T45                ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

; Custom settings are not configured

!

It is definitely not running in CoreXY mode - only one motor is turning at a time when trying to move X or Y.  I've tried adding

M667 S1                                  ; Select CoreXY mode

in the Drives section but no difference.

Found the problem!  As they say in automobile parlance "The problem was the nut behind the wheel"   The X+Y motor wasn't plugged in!  Daft Davis of Devon strikes again!!!   Working correctly now

I'll drill out the Bowden coupler tomorrow and connect the bed heater.  Then I should be ready for my first test print run.

Drilled out Bowden coupler and eventually, with a point filed on the end of the filament, I was able to push the filament through the coupler.  Then heated up the hotend, screwed the coupler into the heatsink and was able to extrude filament remotely.  I also extracted alright.  So one step further

Now connecting up the print bed heater.  Being mains powered this uses an SSR (Solid State Relay) and since there are exposed terminals and it didn't come with a cover, I'm 3D printing one.  Also, connecting mains earth to the printer frame and aluminium bed plate.  All this takes extra time but I don't like electric shocks and take every precaution to prevent it happening.

Bed heater all connected, power switched on and bed set to 110°C.  Heater working perfectly   The SSR has an LED which lights up when SSR is on and can be seen through the transparent red ABS cover.

Next to set up Z probe offset.

Having to print longer drums - at least for the X-Y as the cord came off the end when I tried to home X.  If the cord comes off the X+Y I shall need to replace that one too - so far so good.

Everything now seems fine and calibrating the Z probe - reported height 0.698 mm 0.742 mm 0.741 m 0.779 mm  0.774 mm  0.767 mm.  Average = 0.750.  That's a very accurate figure considering the 2mm nozzle!   Value replaced for G31 in config.g also bed probing set to

M557 X50:450 Y50:450 S200                ; Define mesh grid

Am I mistaken or is it now ready to try printing?  I have a test object to print.  200mm ID and 30mm high.

And we're off!    Currently heating up.

Just a small problem - Z probe too high.  Thought the 0.75mm was a but near the bone!  No trouble to fix...

Z probe re-calibrating 1.022 mm  1.030 mm  1.035 mm near enough 1mm.

Bed probing works fine.  Extrusion not!  Can't get sufficient grip on the filament with the extruder even with the pressure screwed up tight!  Filament isn't sticking to aluminium bed may need some sort of surface treatment.  One bit stuck though.  I'll trying printing slower - currently at max of 40mm/s.

Still too fast so going right down to 10mm/s and ABS slurry on bed for adhesion.

Made a smaller test mode.  Filament extruded alright and stuck to bed with the ABS slurry BUT the Bowden coupler came undone from the heatsink!

Some pics.

I think the nozzle want to be a bit closer to the bed for the first layer.  Currently at 1.5mm for 2mm nozzle.

I'd test with PLA instead. Much easier to work with.
Afterward you could proceed with ABS or PETG.

The slurry stuck well to the aluminium and the filament stuck to the slurry.  Maybe the filament will stick to the aluminium bed if I reduce the clearance.

The X+Y drum is problematic so I'm replacing it.  The filament seems to drop down off the drum onto the motor shaft.

1 hour ago, Chriske said:

I'd test with PLA instead. Much easier to work with.
Afterward you could proceed with ABS or PETG.

Is it?  I have some so I can try it.  In what way do you think PLA is easier - does it stick better to aluminium?  I'm used to ABS and PETG.