Kev, do you or anyone else reading this thread, own British Glass Between The Wars - Dodsworth?
Yes, m, I have "BGBTW", and I can confirm some points ...
In your reply #17, you asked about S&W "rainbow" decor. Bernard's points relating the BGBTW illustrated item and the 1938 pattern number were correct. And yes, the vase in the auction link with the description referencing the BGBTW book is indeed the same pattern and the same colour (delicate blue and green fading into each other in a very rainbow-like way).
And, quoting from the BGBTW book, page 99, catalogue #335:
Described in the Stevens and Williams Description Books as 'light blue and green rainbow cased inside.'
As for "arboresque" ...
BGBTW, page 99, catalogue #331, [sadly not illustrated] was a bowl in "... a style known as Arboresque, introduced in 1933". The description says:
Clear glass, blown into an irregular patterned mould and sprayed with orange metallic salts.
That description of being sprayed with orange salts would fit well with the colouring of the bowl shown in Manley #285 (and #191 in the earlier Collectible Glass book). The photos in the later Manley book are probably ok for colour but many do have a rather dark appearance due to the shelving and background colour and general lighting. But looking closely at image #285 and especially #191 in the earlier book, the colour does show as a thin, "watery" orange with hints of greyish-blue (according to my colour reception). As I said, I think that fits with "sprayed with orange metallic salts".
So, if my thoughts are correct, maybe all of the four colours (as stated by Manley) for Arboresque were sprayed metallic salts. And maybe (as stated in BGBTW) all Arboresque was a mould-blown pattern.
And not only that, but perhaps the meaning of "arbor" in connection with this pattern, was "like tree bark" (such as with oak etc). That could make sense of why we have been thinking of "crackled surface decoration" and have not considered "mould blown".
If so, then I guess some / most / all of the white crackle over pink items referred to are simply not "arboresque". And that would also vindicate Manley in his later book. He only referred to Item #285 as "arboresque". Items #280 and #282 happened to be the first two of that small group for which he used the term "cracked surface decoration".