There were other coins in circulation as well around the cut-off date of 1869 (?)- the 5 and 10 centime French coins,
made in Marseilles on the Heaton presses, and there are still loads about, but nearly always very worn.
Now, if we can assume that these worn coins haven't come into the UK after a long life in French pockets, how come they are so worn?
is it possible that they existed in change for years after the deadline?
Maybe they didn't stand out amongst the same sized new bronze, so the mint didn't spot them, and shopkeepers still accepted them?
If I had gone into a shop in say, 1875, with a handful of copper, would that change have been refused?