Hi Damian,
Thanks for the suggestions.
I gave the minitools program a go; the Seagate drive would not work using it as FAT32 in any segment size (I tried them all) or NTFS, it was also unrecognisable to the PS3. Formatting it with the Seagate program for Win7 in FAT32 and it worked again in the PS3 but not the FVP.
The SATA hard drive in a Dynamode case works after formatting as FAT 32 or NTFS using the minitools prog.
It would appear the FVP and Seagate drives do not like each other and that the Seagate formatting program does something particular for Seagate drives to get them visible.
The minitools program is certainly useeful and will allow me to get the other drive I have working.
Thanks for the help, I will pass the findings to Humax.