The smart thing to do..
For the British the smart thing to do would be to produce their own domestic drone, even if it is more expensive than the US counterpart.
If the UK continues to buy US hardware it leaves itself highly vulnerable. Firstly anything supplied by the US could potentially have a kill switch hidden in it in order to stop the UK from using it against the US in a future conflict, or to prevent the UK from using it against a nation friendly to the US (I'm thinking of a small state near Syria. No prizes for guessing which one). Secondly, the US defence industry is so full of holes that it's a fair bet that any kill switch in a US product is known by China. Half of the engineers in US defence companies seem to be Chinese these day, and the spying rate is appalling. Lastly, even if there isn't a kill switch built in (frankly the Us would be stupid not to put one in given that a drone could potentially be remote controlled by an enemy who was smart enough), the UK would then be dependent on the US for spare parts and repairs, as well as upgrades.