Actually, it is a bypass. The you have gain, you can set to any level you like, and use volume control on your preamp to control the volume. In this mode Arcam SA30 preamp is bypassed, not used. For some reason thise British companies have their own way naming fitures in the electronics, like PVR, I would never guessed what it is. PM stands for processor mode, meaning only amp (processor) is used.
We are not going to convince you Arcam amps are not design to have it's own sound that is audibly different to humans than just being transparent. That's because Arcam knows how to design amplifiers that simply literally amplifier the input signal, i.e. what goes in, what comes out, the only change is the magnitude. So in a blind listening session, it will sound the same to you as the Denon, but again, we cannot convince anyone who believe such well designed amps will sound different when used well within their limits. That said, if there is an outside chance that you could be convinced, or partially convinced, and you want to make sure you are getting the best out of those Focal speakers, you need to grab a power amp that is truly rated about at least 300 W into 4 ohms. Any cheap class D amp that Amir tested and manage to have SINAD>80 dB will do, as it will be as transparent as the relatively weak Arcam amp that seem to like (it's "sound").
So, that's it for amps, all up to you obviously, but as for the speakers, with due respect, TLSGuy is knowledgeable in crossover design, but he can be very biased, so I would suggest if you like what you got, keep it, it just need amps that can deliver the current it needs and it will sound very good. KEF reference class speakers will be better, more neutral/accurate, but that does not mean you prefer them, and pretty much all KEF reference, even some R series speakers will be more demanding (in current/amperes) than your Focal Aria speakers so that little Arcam amp still won't do it. It will do, just not getting the best.. You got pretty of facts now, objectively only though lol..