The "Air Law" comment was directed at both of you!
You cannot receive payment for Flight Instruction without a CPL (in the UK). You can get a FI rating without a CPL (but you must do at least the CPL ground exams) but you cannot be paid for any instruction work.
This is covered in Air Law at PPL level (or it was when I did it!).
Cheers
Whirls
PS - it not a mandatory requirement to have passed Air Law before first solo but most schools will insist on it as part of their own Rule Book.