Almost certainly not. Where do you get the idea that the right ever did apply? Even when an interloper has take the throne by conquest - by the power of their army, not of one-on-one challenge - they have always worked hard to present reasons why their succession was legally correct and not mere power grabbing. As far as I know, no throne in Britain has ever changed hands because of a challenge to a monarh.

I am fairly sure that such a right has never been embodied in statute. To claim it, you would have to show that it was part of the Common Law which has existed "since time immemorial" - which, for legal purposes, I believe to be since the accession of Richard II, the king who created the first formal courts with professional judges. Which, so far as I know, it has not.