Take another look at who owns those pieces shown in the Lesley Jackson (ed) book. Those pieces shown were all for Geffrey's degree show at the Royal College of Art - and are still owned by the family (code number L1 after the essays at the front of the book).
As far as is known, Baxter left the RCA and went straight to Whitefriars under William Wilson. To date there is no evidence that pieces were designed especially for Chance Bros 'Fiesta' range by Baxter.
I would suggest that he chose ruby and blue flashed Chance bowls to produce the cut and sandblasted designs because they would be effective for his purpose and
they would have been cheap blanks.
(Added in edit) However, it is Chance Bros, and is a scarce item.