Assuming that you have put these two albums into the downloads folder in your Core's Music Store and you've waited for a few minutes and still can't see them, I would first restart your Core (I don't mean just wake it up, although wake-up from deep sleep is more or less the same as power off and then on again). If that doesn't give you access to your new DSD downloads, I would probably stop and restart the Naim app.
You could also try restarting the router, then restart your Core and 555.
If this doesn't work either then the question that comes to mind is have you successfully put a downloaded album into the Core before or is this the first time?
best
David
