Sky Stream remote not controlling volume

[CAB5]

New stream customer. Have paired the remotes to two TVS in different rooms (they are not mixed up). They both can turn the TV on and off but both have lost the ability to control the TV volume. Both were aboe to do so yesterday. Have gone through all the reset and re-pair, but the result is the same...TV on and off, voice control etc...everything except volume control.

Does anyone have any ideas?

[CAB5]

Update for those who might be interested. 

After endless resets etc etc, I find the following:

One remote is version 5103.3.8 and it controls the TV on/off and volume perectly.

The other 3 remotes are on version 5103.4.2 and none of them control the TV on/off or volume.

So, seems like a software issue?