Hi lj101,
Yes, it did strike me that the RAF is going to be looking a bit AAR-light if the VC10s are gone by March 2013 and the TriStars by the end of the same year. But I think that the way the PFI is written, AirTanker won't get paid for any AAR services until the new aircraft are actually delivering them. And they didn't set the dates for the transition from the current types; I believe that was another "benefit" of SDSR