"Sandy, wasn't buying them cheaper than the excess mileage charge "
Pretty sure the UK didn't win that one - IIRC the rental was such that a single hour flown beyond the agreement would've made it cheaper to buy in the first place.
And that was a 4-year lease that then took until 2008 to buy them outright.
Still the best acquisition the RAF has made in a long time though...one day we might even use then beyond Strat AT cart horses.