I don't have the Ray Slack book but do have the Sowerby Gateshead glass, Simon Cottle.
The bowls we are discussing appear on the top left hand side of page 110 of the 1882 pattern book.
Two examples of the bowls are shown. the first bowl has the number 1350 as per Agincourt's post.
The second bowl has the number 1350 and a half.
These two bowls have different handle orientation and only pattern 1350 and a half can be hot worked to produce
the shape of mine and Greg's basket.
Pressed glass is not my area of collecting but i always look at the post's in British and Irish glass.
Tim