To whom is a unity candidate accountable?

To whom is a unionist unity candidate (or any other brand of unity candidate) accountable?

Obviously to the voters, though the opportunity to pull the big red handle and eject them from office only comes around once every four years.

In-between elections, what party structure will hold them to their manifesto or campaign commitments?

Not that Nigel Lutton stands much chance of winning in Mid-Ulster, but let’s pretend that he did.

Would he take one whip? Two whips? Is that even possible?

Or do unity candidates end up as glorified independents, outside of a formal party structure, with no undated resignation envelope lodged with their party leader, and free to vote as their conscience leads them and their opinion changes?