Well - it's out!!
Thanks for all the thoughts and advise - butI went a completely different way ~ knowing that there was only wood in there, I borrowed a trick from my ram rod hole drilling tool bag.....
I made a plug cutter!
out of some hobby shop brass I had hanging about
basically just took small cores out of it till I was through:
here's what was left:
no damage to the bore at all
actually had a thin wall of wood still left in the bore [which I popped out with ... yes,... another wooded dowel
]
had to keep sharpening the 'bit' and sometimes cut it off completely but it did work.
Thanks for all the thoughts and advise - butI went a completely different way ~ knowing that there was only wood in there, I borrowed a trick from my ram rod hole drilling tool bag.....
I made a plug cutter!

out of some hobby shop brass I had hanging about

basically just took small cores out of it till I was through:

here's what was left:

no damage to the bore at all
had to keep sharpening the 'bit' and sometimes cut it off completely but it did work.