mobiusnz:
You wouldn't think there are any development expenses in switching back to what they previously offered. 

 

It depends - why did they make the change in the first place?  
Its not a popular one - in fact it has generated a lot of flak (as you can see from this thread) so why do it in the first place?  

To cut costs?  To deliver a new feature?  

At the root of it, I believe the reason for the change from 24 hour history to 6 hour history was a side-effect of enabling digital ad insertion, and was a limitation of the platform provider they being used, not Sky themselves.
To get Ads in stream, they needed to cut down on the replay window. 
The promise was that with the limit to the 'rewind', there would be more 'saved titles' to watch.  Anecdotally from this thread that hasn't eventuated. 

So if they are 'restoring' the rewind maybe the underlying platform has been upgraded? 

In any case, it isn't just a case of 'flip the switch back to the way it was' because they will still want the ad insertion feature active.