Hi Chris,
ORS4 No.1001: General Exemption: The giving of instruction for remuneration by the holder of a United Kingdom Private Pilot’s Licence (Aeroplanes) that includes a Class Rating Instructor Rating (Single Pilot Aeroplane) (CRI(SPA))
This seems to be the most relevant item. Basically means that you can be paid for instructing on a Class Rating Instructor qualification but without the requirement to have a CPL.
I fear it's not a path to untold riches, but may be useful to some folks in a club environment. I think the LAA Coaches worked on a similar basis and this ruling may be a way of bringing that set up in line with EASA rules.
Safe Flying,
WKW