in the same vein there is also a link between the DUP and UVF
I would seriously doubt if this is true - while it is not impossible that some DUP members may be UVF members (and vice versa) I think it stretches credulity beyond breaking point to allege that the two organisations are as closely and inextricably linked as SF and IRA (or indeed SFIRA).
For a start:
1. The DUP is within its own target market a typical, populist "catch-all party". It draws its support from all classes of Protestant and Presbyterian society in the North, and is led largely by middle-class, middle-aged (or elderly) gentlemen, with a strong ethos of religious observance (some might justifiably say fundamentalism).
The UVF and its political associates in the PUP, as represented by the likes of David Ervine and Billy Hutchinson are the polar opposite. It draws its support almost exclusively from the urban working class in and around Belfast. Its political agenda (such as it is) is based largely on representing the interests of this narrow constituency. Most commentators believe that its political agenda is dwarfed by the extent of criminal activity in which it is involved.
2. There are deep electoral rivalries between the DUP and the UVF (in the form of the PUP) and in all but a few greater Belfast working class ghettos the DUP usually wipe the floor with the PUP. I have never seen SF oppose the IRA in an electoral contest.
3. The UVF and PUP remain a ghettoised movement precisely because of the disdain in which they (and more particularly their criminal activities) are regarded by the DUP's God-fearing Protestant constituency. It cannot seriously be said that most SF supporters are similarly disgusted by the existence of the IRA.
4. You never see an SF spokesperson criticise the IRA. They same cannot be said for the DUP vis a vis the UVF.