Ok, an update. The clicking I could hear was actually the air pump relay. Seems the test doesn't make the relay click for 2, only 1. I then noticed that the relay for "Air cut 2" was missing...wtf. I put the one in from Air Cut 1 and the pump relay still doesn't click when I test. Some weirdness there. Not sure why it's missing or why it's never thrown a code before. Anyway, it did it 2 cold starts in a row and hasn't done it since (I cleared the codes both times).
Have ordered the KSTech blanking plates. Got both the ones that go directly on the heads for a full delete and the ones that go between the pipe and the valves. Thought it might be easier to leave the valve with the atmo sensor in place and remove everything else.
Have ordered a Tactrix cable as well so I can get a tune and get the secondary air pump codes deleted at the same time. I'm sick of hearing the stupid noisy thing every time I cold start.