On my MR30, the rotor is part of the hub, remove the caliper, remove center nut (axle nut), it all comes off in on piece
On my 240K, the rotor is bolted on to the hub, remove caliper, remove center nut (axle nut), it all comes off, undo 4 bolts holding rotor onto the hub (on the inside of the hub), give it a good smack with a big block of wood.
I don't know if the HR30 is the same,
Nigel