After much help from Dave, the solution was the following.
The /proc/pci showed the Cardbus bridge memory at 0x73000000. Dave suggested a memory window of 0x73010000-0x7301ffff which worked a treat and then card-services could recognise the card when inserted.
The next problem was that although card services recognised the device it had problems talking to it : The symptom was (on insertion of a D-link DE-660 ethernet card)
May 27 10:28:33 lafeu kernel: pcnet_cs: unable to read hardware net address for io base 0x300 May 27 10:28:33 lafeu cardmgr: get dev info on socket 0 failed: No such device
The same problem produced a misleading (to me at least) error from ide_register about IRQs on insertion of a ATA-IDE 1Gb hard disk.
The solution (thanks again Dave) was to remove the default IO-port range which was the problem and specify a new IO-port range
based on the IO-range of an ethernet card which was the only other device on the same bus (which had an IO address of 0xa800 from /proc/pci)
..... and finally it all works. !