Transatlantic shipping, British import duty and something like 18 per cent tax. The reason Britain's economy does so well is it is exceptional at protecting local industry by whomping huge import duties on companies who want to sell their stuff there. So... on the upside... your economy is booming. On the bad side... MAC is stupid expensive.
OOPS! I just saw it's an ebay link. Thought it was a "why is MAC so expensive" general question. SORRY!