regret I can't help with the answer regarding No. 2614 - although can say that according to the Bagley Glass book, the Nos. 2506 and 2616 are "consistent with Sowerby plinth numbering. Have attached pictures of all three numbers, in case of interest, just to show the differing script forms. From what I can see, the 2614 plinth shape doesn't appear in the Bagley book. Of course, it might seem that these Nos. being not too far from each other numerically, there might have been a connection, but no evidence for this.
I also pick these things up whenever I see them - now seem to have a box full
