Buying Diamonds in UK vs Elsewhere

Hi there

  I am looking around for a diamond ring of approximately 1.75ct-2ct plus. At the moment in the UK, a 1 carat diamond ring set im 18carat gold would cost nearly £6,000, so I can only imagine that a 2 carat would more than double its price. I have seen a 1.5carat going for approximately £12,000 so far!

I would be grateful if anyone can share with me their experiences on buying jewelrry outside of UK at a more affordable price. Also, if you don''t mind the approximate price of the diamond.
In particular, I am thinking of going to Singapore or Dubai to look at diamond jewellery as I have heard that they have good diamonds at affordable price, though I am not sure about the diamond quality.

Can any confirm/enlighten me?
I am also wondering if the price range of Tiffany''s in UK would be different to the Tiffany''s in Asia, due to price discrimination?
Any thoughts?

Thank you