Hello Pete... in your link to the Scott collection - the Pierce vase with seagulls and waves, item 418 shown on page 131 - the letters HRP after his name are, according to C.H. (C20 Glass - Vol. 1) the initials of his facsimile signature. There is a picture of the Scott vase in said C.H. volume on page 171, and on page 168 there is some useful information regarding Pierce's work in the late 1920- early 1930's when he was employed at Stonier's prior to being employed as a designer at Stuart in the immediate pre-war years you mention.
There is another picture of your 'link vase' on page 10 of Nigel's collaboration with Jeanette Hayhurst (ART DECO TO POST MODERNISM) where it's described as a "bucket shape vase cut with birds flying between waves, designed by A. E. Pierce" - not sure why there is a difference in the quoted initials - perhaps some commercial reason.
Unfortunately, this still leaves us high and dry as to the meaning of the initials N.R.D. on your vase posted here. Shouldn't speculate, but wonder if this has some connection with one of the senior Stuart family members/directors who were also involved in cutting patterns/designs - just a thought. But since it carries Pierce's own name that would seem unlikely - perhaps just another variation on his own initials.
But the point of all this waffle was to say simply that if you read C.H. - page 168 that I've mentioned - it does appear that additional information on Reg. Pierce is held by Broadfield House Glass Museum, and always a chance that they will be able to help you in your quest. So certainly worth contacting them.
Unfortunately, no one has yet surfaced to confirm if ANY of Pierce's work - whilst at Stuart 1937/39 - has ever been found marked with the Stonier -S-. so perhaps presently not possible to say if any of his marine type of designs went directly into shipping line use, although the obvious connection re waves, seagulls and fish etc. might tempt us to think so. Of course, someone may now be able to correct me on this, but maybe as his work was a bit special and limited in production then perhaps not.
I know that Stuart had family links with Stonier, but didn't that that they owned Stonier. I've had some ordinary pieces with the -S-, they're not that difficult to find even now.
Unrelated to Stuart completely, but worth mentioning, is another item from the Scott collection - No. 421 on page 132. This is a red core vase cased in light blue, and quoted as being English mid C20, although it has massive similarity to a Jan Baranek pulled lobes vase designed around 1965 for Skrdlovice. There is a picture in Mark Hill's book 'Hi Sklo Lo Sklo' on page 27 - although the book example is green and topaz.