We don't know actually what it looks like. The picture you post is like one that appeared in Hello Magazine - I question the authenticity as the rose tiara is a delicate small piece and the one behind supposedly the Delhi Durbar Diadem is massive in real life, in this photograph the rose bandeau appears to be half the width. I'm not sure that it is that large. Also the exhibition you quote was in 2002 at the V&A (according to your link) this is now 16 years ago. I will be very surprised indeed if this beautiful little tiara appears again. Princess Margaret wore many pieces of jewellery with a rose theme (for obvious reasons) and yet she never wore this ! It's not coming out of the vaults any time soon !
And what a lovely exhibition it was.
My favourite tiara from that exhibition was Princess Andrew's - and the note on the label made it clear that it was there with Prince Philip's permission.
That was the V&A's way of celebrating the Queen's Golden Jubilee (all the palaces etc did something special for that event).
I don't remember the Strathmore tiara so it didn't make much of an impression but there were so many to see it was hard to take them all in anyway.
They weren't all from the Queen but from a range of people - including Madonna's.
I hope whichever one Eugenie wears that it is chosen to go with the dress and her veil etc so that it isn't hidden or lost in her hair. It needs to complement the dress and not detract from it.