I noticed late last night that the following channels were only giving me a blank black screen. ITV, ITV+1, ch4, ch4+1, CH5, E4, E4+1, Film4, More4, ITV2. All other channels were fine. I could receive all channels on my TV using its Freeview tuner so it had to be an Aura fault. The problem was still there this morning. I did not fancy having to retune and set up my favourites again so I pulled out the power lead (No simple power switch on an Aura) and luckily powering up again solved the issue.