Sorry, the ebayer I bought from was charcoal_design. However this ebayer is no longer registred on ebay.
I'm pretty sure that mine is an American spec' helmet but fits me perfectly and looks and feels identical to the UK spec' helmets. I haven't heard the suggestion about differing shell shapes before, as I said mines perfect.
Mine came as "a present" valued at £40 if I remember correctly. The info' about tax etc is, I think, correct. You may however have to pay and then reclaim the tax etc. This is what I had to do when I bought some kids clothes direct from America.
You pays your money and you takes your choice, but it was well worth it for me.
Happy hunting