New information : 
booted up when plugged into Dell docking station, same behaviour as noted in bug (no laptop display, but external working fine)

I also read that creating an xorg.conf and changing the Monitor section to this could help : 
Section "Monitor"
        Identifier    "Monitor0"
        Option        "DPMS"
        HorizSync     30-96
        VertRefresh   50-160
EndSection

I tried this and rebooted PC.... still no laptop monitor display.

I then opened KDE System Settings to see what screens/monitors were discovered or available . HDMI1 and DP1 were both affected to the external monitor.

At this point, with the tool open, I undocked the PC.
This must have tickled something somewhere because my laptop screen became active.
I then replugged back into the docking station, and now I am writing from the Dell in question, with multiple monitor setup. both screens working, as an extended display.

Its not a fix, but its working.... :)

lspci ->>
[code]
00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 02)
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)
00:19.0 Ethernet controller: Intel Corporation 82577LM Gigabit Network Connection (rev 05)
00:1a.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 05)
00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 05)
00:1c.2 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 3 (rev 05)
00:1c.3 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 4 (rev 05)
00:1d.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a5)
00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 6 port SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 05)
00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 05)
02:00.0 Network controller: Broadcom Corporation BCM43224 802.11a/b/g/n (rev 01)
03:00.0 CardBus bridge: Ricoh Co Ltd Device e476 (rev 02)
03:00.1 SD Host controller: Ricoh Co Ltd Device e822 (rev 03)
03:00.4 FireWire (IEEE 1394): Ricoh Co Ltd Device e832 (rev 03)
3f:00.0 Host bridge: Intel Corporation Core Processor QuickPath Architecture Generic Non-core Registers (rev 02)
3f:00.1 Host bridge: Intel Corporation Core Processor QuickPath Architecture System Address Decoder (rev 02)
3f:02.0 Host bridge: Intel Corporation Core Processor QPI Link 0 (rev 02)
3f:02.1 Host bridge: Intel Corporation Core Processor QPI Physical 0 (rev 02)
3f:02.2 Host bridge: Intel Corporation Core Processor Reserved (rev 02)
3f:02.3 Host bridge: Intel Corporation Core Processor Reserved (rev 02)
[/code]


I'm all ears for more testing... as this makes it easier to recover the display.... (work hours only though :) )
david