Every general election in the UK involves transporting ballot papers to a central location (per constituency). This isn’t an issue.

You don’t actually have to count IRV ballots in a central place; it just requires coordination for the multiple rounds: you can count the first-choice votes in many locations, sum them, determine who is eliminated then, still in those separate locations, count again, now transferring first choice votes for the eliminated candidate, and repeat.

STV is used all over the world and requires the same processes as IRV.

As to Arrow’s Impossibility Theorem

I didn’t mention Arrow’s theorem in the comment you replied to. The compromise I mentioned applies to scoring systems just as much as ranking systems.

And again, the lie about the spoiler effect. RCV still has the spoiler effect, and it’s even worse for enforcing a two party dominance than FPtP.

Citation needed.

The main thing to understand is that RCV/IRV whatever you call it, is still a series of FPtP elections on a single ballot. You cannot fix the problems of plurality by iterating plurality.

But… you can. Some of them, anyway. If there are three parties running, A, a similar party B, and Z, where you prefer A > B > Z, then in a FPTP election you have to choose whether to vote for A or B, and if A is the third-most-popular, it’s a bad idea to. With IRV you can rank them A > B > Z, the third-most-popular party A probably gets eliminated, but you still express your opinion B > Z. That situation is, in FPTP, incredibly common.

The situations in which the introduction of option B negatively affects option A in IRV are substantially less common than in FPTP because of this: B has to be significantly more popular, to the point where enough people switch their first choice votes from A to B, resulting in A being eliminated, but B must not be so popular that it couldn’t win head-to-head against Z.

Calling IRV “a series FPTP elections” ignores the important condition under which those successive counts happen.