Cheers foir the suggestions
Yep, already have a 54G PCMCIA card as that resided in my laptop. However they are wider than the PCB on the desktop card so the PCMCIA->PCI adaptor would be even wider than that.
Here's the case with the lid off. As you can see its not the length of the PC flex riser that I have that's the problem but that there just isn't any space where I can place the pci card other than upright in the pci slot