I can’t see any problem with this and IR35. You hold your own O licence, you pay the lease on the tractor and my understanding is that you can source a tractor elsewhere but why would you since you’ll never match the deal on offer, you pay your own fuel you can use a different driver of your own choosing, and one of the crucial tests for IR35, you can make a loss. I also believe that Kevin Rooney is wrong if he claimed that you need to source your own work, in fact why is he commenting on an HMRC matter at all, if unsure there is a very straightforward checklist on the HMRC website to check if particular circumstances are PAYE or not.
I cannot imagine that a company in any industry would guarantee subcontractor a profit margin, turnover maybe, but profit never.