These are Stuart Strathearn, not
"Stuart Crystal Studio". I've checked p 437, I think it's misleading. I'm not sure something called "Stuart Crystal Studio" even exists.
This Iestyn Davies design comes in pink and blue as well - it is inspired very much by IoWSG Summer Fruits, much as his Stuart Strathearn "Ebony and Black" is inspired by IoWSG Azurene. He trained for a while at IoWSG before going to Stuart Strathearn.