Reference to what? i'm sure you can look it up.
Great Britain assisting Chile is not new, as a matter of fact there was at least one war British ship involved in the bombardment of the coast of Boliva, when that country had a coast line after they were done ,Bolivia ceased to have access to the ocean, meantime Argentina was negotiating a border dispute with Chile for the lands below the colorado river all the way down to tierra del fuego , coincidentally the one deciding that was none other than Great Britain acting as referee in border disputes.(1870s more or less)
Giving Argentina all lands south of the colorado and east of the andes , as you can see as far as Britain was concerned the falklands were paid for years later with that verdict..
Now when it comes to acquiring debt ,for whatever goods or services, it is done in the name of the country and is binding, so refusing to pay for armament sold to Argentina is not Britains concern what government did it.
If you have any doubts see how well you do when your ex wife uses your credit card , i'm sure you can swiftly slap that explanation on the banks face and no doubt that will work every time.