[martinw06]

the barrel is held in by "shear head" bolts. they only come out with a hammer and drift or punch. so first answer to your question is yes you can remove the barrel but you can't poke anything up it to remove the broken key. i would find a friendly locksmith to talk to. if you need to remove the barrel to take it to him, it's a ballache (steering disassembly). no idea what a callout fee might be for him to come and look at it.

you, sir, have been damned unlucky.