"I suppose it is possible that the review will conclude that no additional F35 orders will be placed during this review period (ie before 2025, as stated by AM Knighton)"
But even if that happens (and I really cant see why the finances are going to be better in 4 years time) i'll be several years before they turn up - The UK will only have 48 (or 16 active as per Evalu8ter's post). I can see the USMC being a permanent addition to the QE