Cheers!
A real PITA, but at least you know you have healthy drives now. Kicking off a smartctl self test is not a bad chron job for the wee hours every month or so. No insight on why the webgui worked while command line didn't. I gather from the Nas4Free web site that they are really keen on users doing everything through the webgui, so they've given it some thought, methinks. Be interesting to read whatever script the recovery button kicks off. I'm happy for you.
Me too! I only had to recover one drive with UFS File explorer and I think that might even have been part of my fault running various tests and trying to recover the superblock.