Paul, Chris's third photo of the mark in his opening post clearly shows the peacock head trademark below the lozenge for 20 March 1878 - Parcel 7. I can confirm that all the photos I have of the marks from the 'known' patterns in this bundle also have the lozenge plus the peacock head trademark.
As to the pattern number of the piece shown by Chris, the first pic in my reply #2 quite clearly shows it to be pattern 1349 (as does Wayne's online catalogue). The typeface used in the Sowerby pattern book IX sometimes makes it difficult to differentiate between '3' and '5' and '8' when seen in isolation but not when you compare the digits on different pages.
Thank you, Paul, for posting post a pic of the design representation for the contentious RD 319586 so that we can actually see now the design that seemed to be causing so much confusion to all and sundry. Cottle and Thompson were quite correct in that it shows a 'biscuit jar', and you were correct in saying that it bears no resemblance to Chris's pattern 1349 'thing' (which would appear to be a vase or spill after all).
Page 3 of the Sowerby pattern book XI (1885) shows six 'biscuit boxes' (sic.), all from registered designs, as follows:
1032 (RD 260404-405 of 12 February 1872)
1074 (RD 281933 of 22 April 1874)
1074 1/2 (RD 282663-664 of 1 June 1874)
1202 (RD 307690 of 13 Feb 1877)
1365 which is, despite a little artistic licence from the Sowerby draughtsman who specified 'ears' or 'handles' on the base, a pretty clear match to RD 319586 (see my attached pic).
1405 for which no corresponding RD number has yet been determined (but was most probably registered in early 1879, though there was a design for a biscuit box RD 328740 of 4 November 1878 - Parcel 10).
In any case, I thought I would try a different approach that may possibly lead to more fruitful results....
Sowerby pattern 1349 appears at the bottom of page 6 in pattern book IX (1882).
Despite the odd anomalies in the Sowerby pattern numbering 'system'(?), the bulk of the patterns on page 6 which are from registered designs appear in the design bundles of
14 May 1878 - Parcel 9 (RDs 321368-321379)
25 June 1878 - Parcel 10 (RDs 322819-322825)
12 August 1878 - Parcel 6 (RDs 324929- 324932)
16 August 1878 - Parcel 11 (RDs 325096-325101)
The bulk of the patterns on page 7 which are from registered designs appear in the design bundles of
4 November 1878 - Parcel 10 (RDs 328740-328751)
13 December 1878 - Parcel 16 (RDs 330348-330352)
and on into early 1879.
Just looking at the pattern numbers around pattern 1349, most appear to be from designs registered between June and November 1878 (so that would be RDs 32XXXX).
Even so, I've looked through my reference photos within the date range and RD number range without any sign of that elusive pattern number 1349.
Fred.