There was a serial/parallel interface unit for the PCW machines which plugged onto the system bus connector. So you might be able to get the data out that way -- if you could find the interface and the software to drive it.
I never had an Amstrad PCW but I seem to remember some oddity with the drives. Something like the original drive (A
was 40 cylinder, the add-on drive was 80 cylinder. The 40 cylinder driver was a 'flippy', you could turn the disk over. I am not sure the add-on drive was, it may well have had 2 heads
FWIW 40 cylinder drives with 2 heads existed and the disks were not data-compatible with the flippy type. One side was effectively recorded in the opposite direction (the motor did not reverse on the 2 head version when you changed sides...)