Helmet crest from Hadrian’s Wall

[arminius]

Ok, hopefully somebody from Britain can help me out here:
Years ago I visited all the museums along Hadrian’s Wall. In one of them a helmet crest made of sea-grass (?) was on display. I took pictures and wrote down some notes. Unfortunately pictures and notes are nowhere to find – big disaster!
So, is there anybody who has seen the darn thing and who can give me some information about the crest?
I need the stuff because I’m currently working on the “helmet-chapter” for my latest book.

Thanks!