Nope, I don't encrypt drives, only individual files (and that rarely). The contents were recognised immediately by the TestDisk utility, though it wasn't able to fix the partitions to be recognised by Windows. Also tried to take ownership of the drive, but it wouldn't let me (I couldn't get beyond the Properties, as the OS couldn't see anything there... 0 bytes).
I elected to individually copy folders using the TestDisk utility, and that seemed to work. It certainly found more files than PC Inspector did and was able to copy everything it found (PC Inspector couldn't copy a file 10 per cent of the time). Took all night for a 120 GB Seagate.
This morning I connected a 200 GB Maxtor and got... two more unrecognised partitions. This time it makes sense, however, as TestDisk shows they were formatted in ext3, not NTFS. TestDisk still seems able to copy the files, however, so I don't have to connect the drive to my Linux server.