This comment on this Dorset Museum page seems to suggest that it is there, or at the very least, a facsimili of the Ooser is there:

>>The Dorset County Museum houses many rare and intriguing objects from the world's finest Thomas Hardy collection and in July 1997 opened new galleries about Hardy and the writers of Dorset. On display are paintings (R.G.Eves' 1923 Portrait of Hardy), personal belongings -- and original manuscripts of Hardy's great works. Here you can also step inside Thomas Hardy's study; come face to face to the eerie Ooser; follow the Dorset riddler trail; try computer interactives' hear poetry and meet Hardy's fellow writers: William Barnes the Dorset poet, the Powys brothers, Sylvia Townsend Warner and Jane Austen.<<

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