Best place to buy diamonds online/in-store in the UK vs US

[Just_Starting]

Is it worth buying from the US for someone (me) living in the UK? I''m looking for a diamond around the 0.5-0.7 mark, prefer VS2 or better clarity, GIA ex cut as a minimum. Colour D-G (probably E,F). I mention the spec as this could mean it isn't worth ordering from the US over the UK due to not saving enough.

I've heard good things about James Allen on here, but not seen anyone that has specified they have bought from them in the UK on here?

Thanks for any help.