Paul, whether Stewart's opening sentence you quoted in splendid isolation, above, is as you characterise it to be, or not, the rest of his post makes some sense to me.
Now I, too, will try to do the topic to death - due to the simple fact that a player's ECF grade can be rising at a time when his FIDE rating is falling, and vice versa, it must be clear to all that we are dealing, not only with two separarate systems, but two disparate systems.
Your original post in this thread begins and ends with pertinent questions -
Paul McKeown wrote: ↑Sun Sep 01, 2019 6:55 pm
What are people's view of the best correlations between bounds for tournament sections and/or grading prizes, please?
One could use the formula of FIDE = 7.5 * ECF + 700.
However, that seems to put most ECF grades - to my eye anyway - at too high a FIDE level.
What do others suggest?
You seem dissatisfied with Stewart's, above, response - perhaps because he refuses to cooperate, here, in trying to get the two systems to come closer together and kind of agree more with each other in a better/best possible fit?
In my view, what we are dealing with here is a form of "one country two systems" situation.
And, it is not usually easy for that sort of situation to persist for very long. (China and the UK agreed 50 years in the case of Hong Kong - but it now looks unlikely to persist that long.)
The ECF's grading system and FIDE's rating system have existed, side by side, for about 50 years now, in some form or other.
The ECF grading system, for (*all?) its membership, since the late 1950s and the FIDE rating system has been around since 1970 (initially for only masters 2200+, and in 1974 containing only about two dozen male ENG players and a single female - Dr. Jana Bellin at 2250).
[•Note - the USCF stared using an Elo system for its entire membership from 1960 onwards.]
Of course, both systems have undergone significant changes, since, even with some convergence, but remain separate and distinct.
In my view it is wrong to try to reconcile the two in more than a passing way - just to draw rough, but ready, boundaries and to do approximate conversions of ungraded players with FIDE ratings in order to try to ensure they play in an approprate section.
Unfortuntely it is where some of those approximate converted ratings meet the somewhat arbitrarily chosen boundaries that the most accuracy is required, for both, but is very difficult to achieve.
And, therefore I'd suggest that - in the final analysis - either all measured chess performance in England should be transformed to conform to FIDE requirements (and so become FIDE rated, thus making the ECF grading system increasingly superflous and eventually redundant).
Or, since that is highly unlikely, only ECF grades should be used in England with ENG players' FIDE ratings largely ignored, here.
I believe the reciprocal already happens on the mainland, and elsewhere in the chess world, with foreign federations (usually only operating with just a max. of 2 sections) assigning unrated ENG players a '0' (zero) rating, thereby ignoring any ECF grade!?
In England there seems to be a temporary place for a conversion formula of some kind - with organisers willing to use/convert FIDE ratings for the purpose of defining sections and allocating and pairing ungraded players within some, or other, rough but ready section boundaries.
And, Paul, therein lies the problem - as you struggle to smoothly implement "two systems in one country" when, strictly speaking, only one will really do because although they have similarities they are basically different and cannot be cobbled together, satisfactorily, in an elegant, mainly seamless fashion.
Again, as in other spheres, it may be time to choose between conforming largely to some form of continental metrification, or making a UDI and reverting, almost wholly, to English eccentricity - rather than continuing to persevere, perversely, with a mixture of the two, which I admit is easier said than done.