HMG hasn't compleletly closed the door on an eventual F35A purchase, but the official position is that any consideration of it will be in the context of Typhoon OSD. In the meantime the assumption seems to be that 5 Typhoon sqns and a slack handful (2? 3?) of F35B sqns will suffice when Tornado goes - unless the rumours of 1 or 2 extra Typhoon sqns (Tranche 1s retained) come to pass...