Since at least yesterday it has not been possible to withdraw SBD for BTC via blocktrades.
I could not find an announcement about this, nor an estimate of the downtime for the pair - or indeed, whether this is permanent or not.
It's possible that I missed such an announcement completely.
A quick search over OpenLedger appears to reveal that they do not support SBD<->BTC either.
Any other options that you know of?