Wedgetail looks to have been maturing nicely in Australian hands, with some fairly major early teething troubles now apparently ironed out and the system reportedly working well, having achieved FOC in 2015. It's currently undergoing a major programme of further upgrades, due to be completed in 2022. What I don't know is how closely what the Wedgetail offers compares with what the UK would want, but on the face of it the timing could be propitious and the degree of commonality with P8 advantageous too. As to cost, Turkey paid $US 1.6 bn for its 4 examples and Australia probably something comparable for its initial 4 - although subsequently exercising its option for 2 more apparently cost less than $US 300m. Worth a close look as one of the options, I'd have thought.