at one stage the EASA proposals appeared to suggest a CRI could be paid without a CPL!
I am not up to date on this (no need to know) but I think that proposal got killed off. You now need the CPL exam passes (9?) to be paid. You don't need the actual CPL though, IIRC.
I also wonder what kind of work a CRI might get, given how many hour building instructors there are, working on £10-£20/hour and a zero retainer. If you have a speciality, that might be different.
For 100 hours per year that is a £4k difference. Coming back to the original post, that is about 1/3 of a Rotax!!
The actual aircraft is somewhat different as well... wouldn't you say?
I am sure my lawn mower burns even less, and might even be faster in a stiff headwind.