While I don't know the answer to your question, I had a similar experience with a No.4 Enfield I wanted converted to .308. It was a new condition, unfired Mk 2 and I wanted to sell the original barrel and told the gunsmith so. Beyond doing a generally poor job on the conversion, he milled a huge relief cut around the barrel at the chamber area in order to remove it - said it was too tight to get off otherwise.
Beyond being mad, I remember he told me "if you want to sell it, we can braze in a collar, it'll be good as new." While deeming that "good as new" is pretty laughable, it could be an option if you want to use your original barrel - though I would contend getting the barrel off without having to make a cut in the first place is the better option.
