Hi Mike,
Pleased to hear you are now OK,
It is important to remember that for Album Art & Names, YouTube and the Radio, the Brennan Units are accessing public, 3rd party (ie NOT under Brennan control) external, internet services. The owners of these services keep on changing them
without real regard to who or what may be using/relying on them OR the (local region) internet access to them my go down. In such circumstances it appears that the Brennan has gone wrong when in reality it hasn't.
If the change is major it will affect all Brennans and there will be a hiatus in service while Martin modifies his code to cope (resulting in a new software release).
In you case it was evident that other Brennans were working OK so it was either a software corruption (SD Card failure) of your Brennan or a local area failure of the internet connection to the service (YouTube was down locally).
Fred