You are fundamentally and essentially wrong, but are temporarily and partially right.
Your simplistic claim was more wrong than right.
The bulk of the fleet is multi role CAPABLE now (though that capability isn't being exercised, though it has been demonstrated and could be made available), and by the time Tranche 2 jets represent the bulk of the fleet they will be swing role capable.
Once we have four Typhoon squadrons (2013?) I would expect the MR work up to begin in earnest.