Would an angler catching fish to order use a hook like that, or is it possible, as I initially suggested, that it could have been a long-line victim?
You mean caught and discarded prior to being collected by hook and line for the zoological trade, or caught and retained live by a long-liner and then sold on to a zoological trader? Unlikely in either case, long-liners tend to target pelagics and G. cirrhatum is a demersal species, and long-liners don't have the facilities for adequate live retention.
The hook doesn't look especially heavy to me, where you could encounter a wide range of species and sizes it's better to err on the side of caution. The idea is to get them into the live well as quickly as possible, this isn't sport fishing we're talking about.
My impression was that commercial long liners are far more likely to cut nuisance species loose as they're an inconvenience on a boat which wastes time (and therefore money)....
That would likely be the snood that was cut rather than the hook under those circumstances. As there's no evidence of the hook having corroded level with the flesh, it has to be assumed the hook was cut at the bend.
With regards doing the op, how much would it cost to get another shark? More than the op and associated veterinary bills?
Probably not for a Nurse, they're relatively cheap and common, but a zoological institution has, as I've said, a legal obligation to put in place appropriate veterinary care where a known issue exists. Once the presence of the hook was known, to ignore it would be to invite criticism from DEFRA during the periodic inspections, especially if the health of the shark continued to decline. DEFRA inspection reports, even for private companies, are available under the FOI Act, and the antis make full use of this to search through them and then instigate harrassment campaigns on even the most insignificant issue.
Running a story about such ground-breaking surgery that goes national doesn't do a place none of have ever heard of any harm does it? Great publicity!
Merlin Entertainments are a big company, of course they are media-savvy. Most people have heard of the Sea Life brand, not everyone knows there's a facility at Weymouth where new specimens are received, quarantined, conditioned and if necessary treated before distribution to other centres. The cost of the surgery has more than been recouped through the associated publicity, they are a business and it's in their own interests to maximise potential, but they are not able to dictate to the Beeb how a story is portrayed.