Update from Pilkington:
Pilkington Activ™ Blue is a durable, on-line coated, self-cleaning glass. It is classified as a Class A coated glass in accordance with EN 1096, meaning that it is sufficiently robust to be placed with the self-cleaning coating on surface #1, on the outside of a building.
Due to the inherent nature of the on-line coating manufacturing process, subtle ‘bands’ may sometimes be visible when the coated glass is viewed closely and in certain lighting conditions.
During manufacture the appearance of the coating is regularly assessed and any non-uniformity is minimized and controlled as far as practicable.
The coating remains in specification and meets the appearance requirements set out in EN 1096. There is no impact on the durability of the coating.