Am I right in saying that 48 was never a declared limit to the overall purchase of F35? I can't recall the 135-sh figure being walked back on. I thought the 48 figure grew out of a statement by SofS/PM saying that they would procure the 48 required to operate from the CVFs i.e. 2 RAF, 2 RN Sqns of 12 a/c. On top of that would be the trainers, trials and attrition reqt. But I stand to be corrected by someone with accurate knowledge.
Subsequent statements by the last SofS seemed to support this when he said that he would expect 12 a/c to be embarked whenever the ship left UK territorial waters, with larger numbers for work ups and high scale operations.