Well it ended up being the fault of the ignition switch, with the lights off, the switch wasn't recognizing that the key was in the ignition, this confused the ICU. Will be picking it up shortly and will thoroughly relish the novelty of fully functional intermittents, and I'm sure I'll be cursing the seat belt and door chimes after a day or two

 

Nice fix. I'll have to remember that an ICU can get discombobulated.

 

It was actually the ignition key switch, rather than the ignition switch.

The ignition switch recall doesn't apply to my car, I'm sure after crunching the numbers it made more financial sense for Honda not to issue the recall for Canada. I'm going to look into this further though.