This pot was sold at the Warren and Wignall auction on 8th February 2017.  It caught my eye because I hadn't seen this glaze before, and now it's mine, it still remains something of a mystery, at least to me.
It's marked as shape number 291, has the CSA Ltd stamp (so dates from 1925 to '34) and has a painted number 1, that must refer to the glaze.  It has a red body, that I think is more highly fired than the usual earthernware body and has a thick glaze.  Both the body and glaze have been ground down on the base as you find on the chinese blue vases.
If anyone has any more insights I would be glad to hear from you.

Mask vase

This vase was sold to me by a collector who had found it himself at the Cottees auction of September 2010.  It was designed it was designed by James Radley Young and dates from between 1915 and 1921.

Double D

Here's another shape 293, painted in DD pattern by Phyllis Way.  DD is one of my favorite geometric border patterns.  To my knowledge it's also the only one with red glaze (referred to as crimson in the pattern books).

Spotty

This covered bowl, is shape number 293 (10 cm in diameter), and was painted in NC pattern by Vera Bridle who worked at Poole for 10 years between 1923 and '33.   I'm not sure what purpose this pot was meant to serve, there is no spoon hole in the seated lid, but later versions do have a ventilation hole and the more typical teardrop finial. A pot like this is shown in the Studio Yearbook, 1922.