Skydriller
This is not a comment re Sherburn (of which I know nothing) but the situation can be poorly defined in practice.
Normally, if you employ somebody under a (mutually agreed, obviously) self employed arrangement, then you must get a commercial invoice from them for their services. You then pay that invoice just like you would pay any other arms-length supplier.
If you have a "self employed" person working and they are paid monthly, regularly, etc then the whole thing is liable to be opened by HMRC.
It also enables the employee to pretend they were conventionally employed all along, and the company is then deemed to have paid everything net, and the payments get grossed up and the company has to hand over the PAYE on the whole lot!
There is more to this than the above of course and the determination of status is done according to a number of indicators. These include regularity of payments, how many other suppliers the person provides their services to, the absence of any contract or any other form of job security (this is essential), etc.
Many years ago, loads of people were self employed in a manner which would not hold water today. Whole engineering companies and whole building sites would not have a single employee on them!