Err... I don't know. Proposing with a fake £10 ring sounds cheesy to me. You can always go shopping together for the wedding bands :-)

I agree it would be cheesy to propose with something fake-looking, but you can buy a really nice-looking ring for that price, that she is unlikely to realise isn't real (unless she's a jeweller). I proposed that way and afterwards when I told my fiancee that we had to buy a real ring, she was surprised that the ring wasn't real. Maybe I shouldn't have told her :)

The problem with non-GIA certificates is that because GIA is the standard, the reason that anyone submitted to a non-GIA authority is that they think they'll get a higher price if they sell it with a non-GIA certificate. In which case you, as customer, are paying more for the same diamond...

Well, the first choice is between yellow and white -- some people want yellow (gold) jewelry.

This is true. As the fiancee wears both gold and silver, I assumed she was OK with both.