That's a very solid case for contractors and almost nobody will have a meaningful problem with it. I've done similar things in the CAD / data management space.
A person with outside perspective, rare skills, experience, and most importantly, is the outside voice able to bring real options to the table along with production proven, time tested ways and means, is worth every penny.
The full time peeps should be taking you out for a lunch or two to network and gain some easy, high value mentoring, contacts...
I would in a second, and have had others invite me for this kind of thing. Some have remained in touch for years, and as they grew, have helped me as I did them.
If we had more of that going on, it would benefit nearly everyone.
But we don't.
The majority case boils down to head count quotas, and cost of labor factors. Often, these are both under specified, leaving managers to find contractors to fill gaps. The larger companies do this and it's chronic.
Such a contractor would likely meet the new "ABC" standard in the linked article, though. Those aren't the positions that are in danger of being eliminated, it's the "grunt contractor" folks who are contractors only because the employer wants to keep a buffer of positions that are active but can be terminated easily.
Either to cover a need for a project that won't last long term or to fill the demand for more fingers on keyboards right now.
Is that not how the US uses them? Then again UK programmers seem to earn much less than US programmers. Outside London it's like £50k for a senior dev ($70k?).
You can go check on any job site, indeed, cwjobs, whatever. CWJobs claim the average is up to £62k for London now, and that's of all dev jobs, not just senior ones:
https://www.cwjobs.co.uk/salary-checker/average-csharp-devel...
Not so sure I disagree with CA overall.
I think that, taken literally, I'd be 0/3 in the ABC system.
I have been in a position (for which I'm super grateful) in which young startups didn't have the funds to pay me my full-time rate, and so instead chose to pay me a weekly rate to work one week out of the month. I like to believe that I provided substantial value in that configuration - usually landing to review code, mentor newer programmers, and help chart direction for the subsequent three weeks (during which I'd be absent).
In this case, I was being paid quite a bit more than the full-timers, not less.
In time, they grew to be able to afford a more complete full-time cadre, and they people I worked with weren't so junior anymore.
I did this... I think half a dozen times. It was a great work config for everybody. If you can afford to travel to the work and you can really bring the fight for 5-8 straight days, I highly suggest it.