Hi apologies I just double checked the (very old) conversation with the SA on WhatsApp, and yes at the time it was 7mm vs 9mm, apologies, I think I know where I got the 5mm confusion from (another project).
So mine is definitely 7mm.
(I don’t remember a smaller version at the time so it may be a more recent change the 6.5 vs 7, but maybe I’m wrong, the sizes in my pics are definitely right this time though ; but also checked my European Tiffany and as you say it’s 6.5 or 9mm now - I’d imagine it’s not a huge difference really 0.5mm).
My advice would really be to see them in person tbh.
In any case I did find scrolling up two mod shots from the SA of both 7mm and 9mm with a 0.07 rg DBTy, in case it helps