I haven't read the loan terms in a while re security. From memory it's a mixed bag of secured and unsecured bonds, and a credit facility. The bonds were rather 'junkish' thinking back to a debt ratings announcement which mentions they were 'CCC' or thereabouts. Pretty bad but expected given the state of affairs. Additionally they have security by being a 50% equity holder!
Could be tax related. A pertinent point about tax savings, like the failed re-dom, is that if such moves were a good idea for shareholders like they stated in their recommendation of the re-dom, then why wasn't it done years a go. None of this wheeling and dealing was done until the CB recap.
If Boart defaulted, presumably drilling contracts would continue under an administrator until a buyer comes along for Boart or part thereof, including takeover of contracts. Any remainder is liquidated. CB make big $$$. CB could be prospecting buyers now pre-empting all types of takeover scenarios whether via cash buyout or forced administration. It's core PE business to do that.
You're right it's a lot of jargon. CB are all about de-risking and maximising returns. I view all company decisions like the above, as murky as they appear, to serve CB. Cynical I know, but PE are hard dirty players.