Thanks fellas. Really appreciate all the comments you have to made.
Hats off to Framiga's reply. I booted up with both drives powered, but the 18GB off the cable. Hoofed it on with the Miggy running, ran scsi mounter (changed tooltype to cybppc.device) & there it all was. Had a squiz around with HD toolbox, all the partitions were there. Saved changes to the fact new Drives had been found & Re-booted! When Desktop loaded, every Icon was where it should be. No problems with the data either. Everything copied & worked a peach.
Now I have the Barracuda on its own, I'm wondering why Im only seeing 7mb/sec at best instead of nearly 15Mb/sec!? This was with 290Mb & 800Mb partitions repectively. The 4 x 290Mb partitions all gave nearly 15Mb/Sec. With an 800Mb, 3.5GB & 2 x 2.1GB partitions, I get 7mb/sec & 3.5Mb/sec on all the others. Buffers are only 80 right now but when the 4 x 290Mb partitions had 240 Buffers, I was getting nearly 15Mb/sec across all of them. This might have something to do with the filesystem; I'm not entirely entirely sure PFS3 is quite right or the hard drive settings are optimum. Perhaps Partition Size plays a big part too. I've gots lot to play with getting this sussed but hey, this is the "Fun" side of Computing which no other platform has ever provided! ;-)
More importantly, I recovered all my partitions & every bit of data is fine. What a result.
Thanks again Framiga, really appreciated. :-)