Hang on..................
I thought at the beginning of your posts you were suggesting that we had to do a test flight of just our flying skills as well as doing the usual 1 or 2 year Class Rating thingy that all PPL's do. Now that seemed odd to be tested yet again for flying skill in what seemed a similar test format.
You then told me that what Dobson et al were saying was effectively re-introduce the old QFI renewal type flight test. Now as far as I am concerned thats fine. As thats a test specifically for that rating. Yes it does test your flying skill, but obviously the aim is to see if you can still teach correctly. No point being able to teach yet can't fly accurately!
Your comment about your last instructional flight you did. Yeah, thats fine, because being Multi Crew, thats what you need to do. You ain't teaching the guy how to fly basics, your building on his/her already demonstrated professional skill.
A PPL is being taught the whole thing from scratch. You need to show that you can teach the basics. Demonstrate them accurately, and fly a SEP (L) professionally, and safely for that trial lesson you can legally do with paying punters!
I think your professional instructor bit is a totally different kettle of fish. Most of techniques are the same but the material is different.
Please correct me again if I have the wrong idea of this proposed new FI renewal, but thats how I read your later posts.