Why is my white silicone render cream?

[UWascalWabbit]

Currently getting silicone rendering done on our home. We wanted a pure "brilliant" white in keeping with the rest of the house, but what we have got is a yellowy peach/cream colour. Photo is of some of the render spread onto card, 24 hours ago, against a piece of white paper. The colour on the wall is exactly the same.
The render material is Johnstone's Stormshield "white" which is the whitest of the shades on their chart. In the tub, the render looks white, on the wall once dried it is cream.
Our rendering guy just says "this is the whitest you can get" but we are really unhappy with the finish and are looking for alternatives. Only one small end wall has been finished so far, the rest are still base coat.
Any suggestions?

Have a look at this company
https://monocouche.co.uk/colours-finishes
And also
https://www.uk.weber/colour-charts/weberpral-e
I’m sorry to say it sounds to me like you might be get fobbed off by your render guy. Don’t quote me on this because I didn’t deal with renders directly, but I was in an industry that occasionally dealt with renders and I don’t recall Johnstone ever been a main player. As far as I’m aware the 2 companies I’ve given you are the market leaders.