So Corsair have sent a new gas canister, however, I'm unable to dislodge the old one despite my best efforts. I've used WD40 and tried to wiggle it free, knock it free, and even used my full body weight to no avail.
I've responded to the open ticket I have with Corsair, asking that they kindly supply a new five-spoke wheel and tilt mechanism assembly. See what happens next!