More than 20,000 see Roman helmet at Carlisle Museum", in-Cumbria January 27, 2014). One of the Carlisle visitors is quoted: "This helmet really belongs here". Indeed it does (if it was found in a Cumbrian field). But it was acquired by an anonymous private collector.
We should not forget that this helmet underwent a rushed restoration "job" before it went under the hammer in London. There has been (as far as I can tell) no scientific study of the helmet.
And we need to question where it was found.