Disco II wheel

Hi, I am looking for a single Disco wheel like the one in the picture. What are these called ? I have already tried two from ebay that dont fit and I am starting to despair.
You may have worked out I am new here. I realise that I should post in the wanted add section, but I am not sure how to list without a picture.

Thanks for the help

Style 6. 18" alloy wheel, as fitted to the ES PREMIUM