You do not remove the breech plug on your Hawkins. Leave it alone. Granted many years ago, (about 30) the breech plugs were able to be removed, but only for emergencies. The newer rifles do not have a removeable breech plug. The only thing you need to take out of the rifle is the nipple. Even the bolster clean out screw is being removed from many of the rifles and in some rifles, they seem to weld themselves in place anyway.

So just get a nipple wrench/wedge puller/hammer combination tool and you should be all set.