Lost volume RN104 and no recognisable superblock on data partitions of either disk

As per the title, I am unable to see my data on  my NAS 104 using Windows Explorer, or when logging in directly as admin (IP) or online. As noted on another thread with similar issues, my problems have arisen since a recent power outage (12 Feb) and may relate to a drive being out of sync due to lost writes when the drive did not shut down cleanly.

Once logged onto my NAS online I see warnings about increased ATA error counts. Following advice from various relevant posts I have enabled ssh and tried a 'mdadm --assemble --really-force /dev/md127 /dev/sdxx' on the data partitions of the two drives fitted in the NAS (/dev/sda3 and /dev/sdb3). The result is 'no recognisable superblock on them both.

I have downloaded my logs and hope a more experienced user can guide me further as to what steps I can take to recover my files. I'm aware the increasing ATA error counts could indicated pending drive failure(s) and would like to recover my data urgently so I can copy it off.