It appears that all of the affected frequencies and channels used to be on the Astra 2A satellite.
They are now on a different satellite - this could be either Astra 2F, the new UK TV satellite recently launched, or (unlikely) Astra 1N, the "temporary" UK TV satellite, which is also carrying the majority of the BBC and ITV channels.
Well it now appears that the channel moves were to clear our Astra 2B.
And the channels cleared out from Astra 2B, and some from Astra 2A, were indeed moved to Astra 2F. And not to Astra 1N.
This was confirmed in a statement today from SES:
"Astra 2B was indeed replaced by Astra 2F at 28.2 degrees East and will soon move to 19.2 degrees East to support the fleet and provide back-up capacity at this orbital position. The channel shifts should now be completed."
Update: 1/2/13 : SES Astra have now said that some channels have moved to 2F and some have moved to 1N. We are waiting for confirmation as to which frequencies / transponders are on which satellite. But could be a while especially if SES left hand does not konw what its right is doing!