I have a reply from my MP, Mark Prisk. He writes

In relation to your question,I understand the reason why more air-time in the media is being given to the decommissioning of arms by nationalist factions, is due to Sinn Fein's "inextricable links" to the IRA. This is in conjunction with their strong electoral mandate makes such a link especially intolerable. It should be unthinkable that a political party with such ties to a para-military organisation can wield such power.

Although it is true that the Progressive Unionist Party (PUP) is similarly linked to para-military groups such as the Ulster Volunteer Force, the PUP's situation there is clearly somewhat different- as they have just 1 member in the Northern Ireland Assembly compared to Sinn Fein's 24.

I do however fully support any moves that will bring peace to the Province and I further believe that all paramilitary organisations should decommission their arms as part of the peace process.