Quoting English law serves no purpose but to confuse and misinform. We have already established that two girls working together is not legal in Ireland. Nobody has mentioned agency but you. Agency has nothing to do with it, working in pairs, be it agency or Indie has a legal implication, but only for the escorts involved. Having said that I do know of more than ten Indies that do work together, so do you, so lets not pretend we don't here Chambers.
In any case, your argument is futile, as the subject matter of this entire thread is the legal considerations for the punter and not the escort. And to that, the answer is simple, the punter does nothing illegal... as it stands...