If it were something current production, e.g. from Savage or Remington, you might get a new factory barrel or a take-off from someone's project and it would be much cheaper, but the quote sounds reasonable for getting a blank supplied and fitted to an old Parker Hale like that.
Fortunately if the bulge is close enough to the muzzle to leave enough barrel, the cut and re-crown is quite reasonable.
If that doesn't work out, let me know how much you "invested" in the PH high rings. I can use another set so if I can afford them I'll be interested.