I'm wondering if this entire thread has missed the point. The OP seemed to be proposing a blanket C2 for any type AC RCD circuit, then did a bit of a back-track.
This is what really boils my P about 'inspectors' who lack the fundamental knowledge and learning to apply some engineering principles and instead just go looking for any reason to find a higher code because they think it justifies their existence.
Absolutely, there are instances where potentially use of an AC type rather than an A, B or F might be innapropriate due to bias and blinding, that's a part of mine, Davesparks and several others on here's specialism(s) every day, but it bears no relation to a lighting radial of 60W BC's in Mrs Miggins pie shop where an AC type is still perfectly acceptable as it provides entirely appropriate protection against the risk.
Sure, the lines have become murky in domesttic installations due to the changes in household and consumer appliances but if you are going to be ballsy enough to make an assertion about risk, then at least understand that risk and be able to justify it. If you think that a circuit might be compromised then simples - test it. Apply a ramp test when it's in normal use and see what happens - if your assertion that it needs a C2 due to DC blinding is true then it won't trip on a standard ramp test. If (when) it does, then you'll know to stop talking ball hooks and give it an entirely appropriate C3.