thanks for the explanation Tricia

, although I'd suggest that to include Parcel Nos. together with the Rd. No., albeit the correct one, is unnecessary and possibly confusing - I don't recall seeing this before.
All pieces which conform to the design protected by Board of Trade Registration 105196, no matter what shape or whenever produced will, to the best of my knowledge, carry the exact lozenge details as shown in your very clear drawing.
It's always possible, of course, that the creator of the history page in your link had some other reason for including Parcel Nos. In the ordinary course of events, I don't get the impression that Parcel Nos. convey special significance, although when searching archives/books to confirm Rd. Nos., then often a Parcel No. is one more piece of information which might help to verify a maker.
GMB members will always help, if possibly, to supply comprehensive Registration details for any glass about which you might like to know more.
Might we get to see more of your glass collection some time?
