Episkopiana,
You seem to ba a tad muddled over the RAF Hercules procurement. The MOD bought the current 25 J's to replace half of the then current 61 aircraft K fleet. The deal was that there was to be no increase or enhancement in capability, merely replacement.
The current surviving K fleet will not be replaced by the J, it will be replaced by the 25 A400M's that the MOD is purchasing.