get the impression from the books that posset pots had long since gone by the C19 - the only feature that might have suggested this is possibly the small looped handles - although by the looks of it more decorative than practical in this instance. Real posset pots seem to have had a spout from which to drink spicy curdled milk.
nothing in Gulliver that comes really close - plenty with rigaree, pincered decoration and prunts of course - the sort of decoration that suggests late C19, but you may not get any nearer than that, unfortunately - possibly vases. Not really my area, but were similarly decorated pieces made of lead glass in 1880 - 1890??