Navaleye,
The last 2 Defence White papers have stated that the manned element of the GR4 replacement will be Typhoon and/or JSF.
The JSF basing study revealed a tentative plan for a wing of 2 small JSF squadrons with a unit establishment of 8 a/c a piece as the JSF element of the GR4 replacement. What is unclear is if this will be IT for the GR4 replacement or whether there will be a Typhoon element.