Re: Well duh!
It depends on your contract. If you are paid by result, not by attendance, then as long as you deliver on everything the contract promises, then non-attendance should be paid.
But this is one of the things about IR35. If it is a contract that is paid by result, then you will probably be outside of IR35 anyway. If it specifies guaranteed hours of attendance that should be provided, that looks a lot like control when HMRC looks at the role.
The problem is that many contractors currently work somewhere between these two extremes.
I decided to work through an umbrella some time ago, a long time before this current brouhaha, but my role specifies pay for days worked, but the assignment and the contract (from what I've seen of it) does not actually specify what hours I work, and pays by the half-day, not by the hour. A half-day is at least 4 hours, and I can only bill two half days in a day. There is no overtime provision (in my contract) except weekends and bank holidays.
The client actually values flexibility, is prepared to bend the rules slightly to recognize the fact that some days are actually longer than 8 hours, and allow me to 'carry' hours from one day to another, provided that I do actually work the equivalent of the number of days billed.
This would be great, except that one of the agent timesheets that need to be filled in as part of the billing process is very strict in implementing the 2x4 hour half-days per day. If you put more that 8 hours on the timesheet, you only get credited one day, If you put between 4 and 7:45 (it only has 15 minute granularity), then you get credited half-a-day. If you put anything under 4 hours, you don't get anything.
So the way that the agency works makes it much more likely that the role would be inside of IR35, although the client is actually more friendly.
This does not overly worry me (remember, umbrella and full tax and NI paid on all income apart from the very limited HMRC allowed expenses), apart from the implied fraud of billing the wrong number of hours for some days in the agent timesheet (my conscience is clear, however, as I actually work more than 40 hours in a normal week). But this is neither paid by result, nor is it strict hours of attendance. Several of my colleagues appear to be trying to persuade the client that because of this along with several other CEST answers, that they should be regarded as outside of IR35, although the higher-ups in the client are pushing back, because they don't want the risk.