Regret I can't answer Mike's questions, other than to ask if he is certain his are PQIW - assuming they are, then they must glow of course. I say this as many patterns, 1239 amongst them, were produced in materials other than Ivory Ware - am I correct in thinking that Ivory Ware is almost always trade marked and has a lozenge?
I didn't really have anything riveting to add to this thread, but just wanted to mention something which I thought of interest ...................
I notice that Raymond Slack also shows pattern 1239 (page 33) as depicted in a Sowerby samples sheet from The Pottery Gazette dated 1st November 1879. This shows the 'woven' pattern decoration around the top of the vase, the same as Roy's pair.
However, again in Slack, there is another example of 1239 shown on page 52, where it appears as one of the items on a page from Sowerby Pattern Book VIII, dated1880.
This time though the 'woven' pattern is replaced with a regular squared pattern, with unbroken lines running
through the design, and although this replicated pages doesn't say as much, Slack describes these Pattern Book VIII pieces as 'articles in gold' - presumably a gold coloured 'Vitro-Porcelain, but I'm really not sure. This squared variety of the design is similar to the small pic shown by Fred - not sure of the source of his picture.
The number of rosettes is 9 on both varieties of the vase.
I've attached pix of Kew images for Rd. 314267 and 314268, from which it would appear that pattern 1239 corresponds to the former and not the latter as indicated by Simon Cottle.
Of course I may well be completely off the wall with all this, so put me right if I'm wrong please

Obviously different moulds used for each design, so as part of an answer to Mikes question then, there were at least two separate moulds used for pattern 1239 in view of the varieties of the rim pattern.