I don't think that a left back is a pressing concern. We have Gray and Neill, plus Taylor, Matteo, and McEvely as backups.
I also think that a lot of people are underestimating Nonda (which is understandable, considering the underwhelming debuts of McCarthy and Roberts), but I would expect him to start alongside Benni and score quite a few goals. From unleaded's video, it doesn't look like his goals are the prettiest, but he can put the ball in the net when it counts.