YQ/YR used to be identified as a "Fuel surcharge" however most airlines including BA have removed that terminology and it is now just identified as a carrier surcharge.
It is still (incorrectly) referenced as a fuel surcharge.
It is also often referenced (even more incorrectly) as a tax, just do a search on FT/Google for "YQ Tax".
So it is simply a change in what it is called - so unless there is no longer any direct link (as you claim) at all with the price of fuel it is still very much a fuel surcharge!
Or will BA try and con everyone as per your attempt to and state it is now a "carrier surcharge" with no link to the cost of fuel therefore no need to be reduced in line with the falling oil price?
Although somehow I sense if fuel rockets again, the story will change back to being there is an influence in YQ with the cost of fuel therefore it will go up.
Or am I just being cynical?