This is V04-147-12 = Moyle x Evesham. This often develops a darker yellow rim after three or four days. I’d have to color code it as a 3W-Y.
I love both parents. ‘Moyle’ is a personal favorite raised by the Late Sir Frank Harrison. It is almost (almost but not quite) pure poeticus. The flower is 96 mm in diameter which is about midway between the smallish ‘Moyle’ and the much larger ‘Evesham’. A few of the siblings would be Intermediate Div. 3W-Y. Other than the whiteness, they don’t look very poet like to my eye. Most look similar but vary in segment width with some being a bit reflexed. None show a rim of orange or red.