very nice model. first thing to say is that I notice Ray Slack doesn't show any Registration for 18th December 1888 - are you sure that is how it reads Fred? Just for the record, Slack's last item for 1888 is dated the 17th of December, and is Registered to one John Shaw & Sons of Sheffield, and is No. 115910.
Unfortunately, 1888 is way beyond the end of the lozenge period, so I can't double check my Kew records for you, although I can of course do so when I next visit.
That's not to say that this isn't a legitimate Registration - it may well be a CLASS IV item that Slack overlooked.
Turning to Registration 359805 dated 18th December 1880 - rather red faced here as it seems I don't have a Kew image in my own records. I've checked the Register (not the Representations Book) and this items is without any description, so no help there.
What a coincidence - both these items dated 18th December - perhaps a portent of some disaster - maybe our crops will fail this summer
So, sorry to be unhelpful, and if you do want Kew images of either of the above let me know some time.