Which doesn’t apply in the UK post Brexit, hence this situation. The UK could cram down interchange fees (such that the EU had) with their own regulation if they don’t want merchants banning rent seeking payment networks.

It still applies in the UK, just not between UK-EU transactions because those are cross border now

The whole point of brexit was to get rid of the sort of fair, efficient, reasonable legislation the EU pushes. Brits want to be fucked over by big US mega corps and are tired of the EU refusing them that right. As a Brit I wish it wasn't true but here we are.

Following Brexit they'll probably be able to jack it up by offering consulting roles to Tory politicians.

Doesn't translate to real life: "1.45% + € 0.05 per transaction"

https://www.mypos.eu/en/pricing-and-fees

That would be the extra price set by that particular point of sale / middleware.

Maybe look at Adyen instead.

Yeah sure, but that‘s all added on by other parties. As far as I know, the layers above VISA/MC are diverse enough (not a duopoly). If that‘s true you could rely on the market to drive down fees if it‘s profitable.