[ubuntu-uk] Clock settings greyed out

[Dianne]

Running Ubuntu 14.04 LTS. Today my clock doesn't show in my menu bar, 
settings on clock tab are all OK but greyed out. Time is set to auto 
from internet, and I can change settings on this tab OK. I'm sure it was 
OK yesterday! No updates to system yesterday, though I've had quite a 
few over the previous few days, and I'm sure clock displayed OK since 
those updates.

Thanks for any advice,
Dianne