daveyWhat printer driver do you think you have installed?? This time does not matter how you try to find out

No the penny has dropped here. Absolutely brilliant circumstance of confusion for me. I love it
Edit:There is one file I would like you to keep/make a copy of before you do anything below, I have constructed the file and I think it should be correct for your situation. I would like to have a look in that. Don't post it in forum, let me know when you have it and I will PM you an email address used for this sort:
/etc/cups/ppd/HP_LaserJet_6MP.ppdIt is an ordinary looking text file. Back to the problem.
[carol@localhost ~]$ lpoptions -p HP_LaserJet_6MP
The highlighted is is one of your print que name (in CUPS speak) if you have installed more than one, which is quite sensible and using the same physical printer. In this case it is the printer in your system
auth-info-required=none
copies=1
device-uri=hp:/par/HP_LaserJet_6MP?device=/dev/parport0
another important line for the knowledgeable
finishings=3
InputSlot=Lower
job-hold-until=no-hold
job-priority=50
job-sheets=none,none
marker-change-time=0
number-up=1
printer-commands=AutoConfigure,Clean,PrintSelfTestPage
printer-info='HPLaserJet 6MP'
You really have a 6MP
printer-is-accepting-jobs=true
printer-is-shared=false
printer-location=hp
printer-make-and-model='HPLaserJet 6mp hpijs pcl3, 3. 11. 10'
This may be quite a good hint. I was very close at missing this too notice the mp6
but the hpijs made me stop and think.
printer-state=3
printer-state-change-time=1327108616
printer-state-reasons=none
printer-type=10522652
printer-uri-supported=ipp://localhost:631/printers/HP_LaserJet_6MP
What got me is that there really is such a driver as highlighted below, which you
davey must have selected.
Notice the
lower case mp6 (I have overcome a forum html problem by adding spacers in 3. 11. 10) to show the real text
printer-make-and-model='HPLaserJet 6mp hpijs pcl3, 3. 11. 10'
My install uses the following driver ( there are more that could be used, but it was just chosen at rando as I did not know what you had):
printer-make-and-model='HP LaserJet 6MP - CUPS+Gutenprint v5.2.7'
Just before I go further:
[gert@localhost ~]$ lpoptions -p HP_LaserJet_6MP -l
[carol@localhost ~]$ lpoptions -p HP_LaserJet_6MP -l
PageSize/Media Size: *Letter A4 Photo Photo5x7 3x5 5x8 A5 A6 B5JIS CDDVD80 CDDVD120 Env10 EnvC5 EnvC6 EnvDL EnvISOB5 EnvMonarch Executive FLSA Hagaki Legal Oufuku w558h774 w612h935 Custom.WIDTHxHEIGHT
PrintoutMode/Printout Mode: Draft *Normal High
InputSlot/Media Source: Default PhotoTray Upper *Lower CDDVDTray Envelope LargeCapacity Manual MPTray
Duplex/Double-Sided Printing: DuplexNoTumble DuplexTumble *None
Quality/Resolution, Quality, Ink Type, Media Type: *FromPrintoutMode 300DraftGrayscaleK 300GrayscaleK 600GrayscaleK
[carol@localhost ~]$
Above in my opinion is a bit suspect, I think this may be an
inkjet driver and there is some screw up here which I don't quite understand as it is the first time I have come across such a setup. (but I don't remember well either

). I will check on the 6MP.
The situation is following:
1.. You hang in here and carefully follow a few more steps, please don't rush and try to fix things, there may be some gold nuggets of information hidden in all this.
2.. I would recommend at this stage you change the driver to My driver shown above, but if you do not want to do that we can carry on with what you have and figure why it does not print.
3.. When you have chose your direction, we will attempt making sure that CUPS does the right thing by printing out a specific file from the command line.
4.. I have just looked in my Laserjet 2300dn and this also has parallel printer port, if need be I will find a printer cable and run with that.
This should end up with knowing that the CUPS is working Then we will look at the various applications as they may each have individual problems.