@smerf and thread
SUCCESS...and it was a lot simpler than all the threads on the net/opinions made it out to be! This is the combo...
* Standard A1200 IDE controller (*NO* 4 x IDE adaptor)
* 8g transcend CF card in a 3.5" single CF card adaptor connected to the header on the cable closest to the IDE controller. Partitioned to 3gig ONLY on first part of CF card (success gone once there was more partitions used). Jumper set to "slave/master" and not "master/slave". (Will go to a 2/4g SanDisk for reasons too long to explain here).
* 2.5" to 3.5" x 2 cable
* Slim CD model CR-176-B with 3.5" convertor connected to the header on the cable furthest from the IDE controller. Pin 28 removed on adaptor (maybe not necessary).
* A500 power supply with CF power + CD power + floppy power all off floppy power header
* Kickstart 3.1 (necessary?)
Booted "without startup-sequence" and ran setpatch. Booted "without startup-sequence" again. Using a mountlist and all the CacheCDFS bits I previously had on a disk from stuffing around last time, I mounted CD0:....voila! Works. CF accessible, and CD accessible. Admittedly, it's not PROPERLY setup yet, but it IS working, recognising CD's, allowing access to them and so on - CONSISTENTLY and RELIABLY. I did *NOT* use IDEFIX or similar software.
Even had it working with/without a Blizzard 060 card connected but NOT "software installed", and also a 80g HD as the slave instead of the CF card.
If you need more details smerf just ask! It was a very frustrating process getting this far, so if I can help I will!