It reads to me as a bathroom without RCD protection OR supplementary bonding which rightly attracts a C2
I’m imagining the regulation number quoted is an error and the wrong type of bonding not present has been selected on the EICR software.
Thats the way I read what hes trying to say, although the reg number (and the wording) seem a big mixed up. I generally word as "Lack of supplementry bonding to bath/shower room where conditions permitting ommision of this are not met - (C2)" although if the only change to made it comply would be to add RCD protection to a circuit that only supplies a light fitting that is either class 2, SELV, or having no accessible metal parts as installed (like a 2D fitting, its class 1, but its all plastic on the outside once the diffuser is in place) then I might be temped to down grade to a C3
Of course as you say, you'd have another C3 for the cirucit having no additional RCD protection, likely another for the same to concealed cable, and now one for domestic lighting without RCD protection (although I'd probably wrap that up with the concealed cable observation as one combined observation)