Does anyone know of any car hire company that would not have an exhorbitant one-way fee for picking up a car in Dublin and dropping it off in Belfast?

I know that high oneway fees are the rule between different jurisdictions but wondered whether there was a Northern Irish exception here as there is in so many other contexts.

Dan Dooley, on their Belfast page, state that they offer oneway cross-border rentals without oneway fee but it only seems to work North to South and not South to North.

All the majors seem to charge a oneway cross-border fee in the region of £130. I guess the alternative is to take the train to Belfast but it is a bit of a hassle to have to drop the car, take the train and then pick up another car in Belfast so this would only be my "second best" option.