Paul Jameson 36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project). Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period). Now Archivist once more - but not Machine Registrar.
If you want to be fussy the correct horn has a piece missing from the rear shape in the casting. I don't think it's any different from the other Ariels of the period (before and just after WW2). I don't know when the plain shape came in. Nev