the reaction to ultra-violet light would more likely be caused by manganese, and should appear as a dull grey/green - it's been around for eons mostly as a colourant, rather than a de-colourant which would be its use here (that's assuming the reaction is a greenish appearance).
The top down handle suggests manufacture was some time prior to 1860, and bearing in mind the folded top rim then could be nearer the beginning of the C19 and possibly formed, initially, by a dip-mould - this provides the 'berry' decorative moulding - the piece is then removed and blown again to finished size - but I am guessing somewhat with this suggestion.
Are there any mould seams on the outside surface of the glass? Early blown-moulded pieces, made in part moulds, might show evidence of seams which could be removed by fire-polishing, hence the pointil scar where this was carried out and for which the jug needed to be put on the rod.
Can't see too clearly detail on the underside of the base - it looks almost stippled, but the presence of a sharp scar indicates this piece was finished on the pontil rod, then snapped as a final act, after fire-polishing for example.
These various features - including seeds - suggest a genuinely old creamer or milk jug, though it's not impossible the piece is more recent and made to appear older. Does the colour suggest a lead hue perhaps?
Doubt that you'll get as far as origin, but English wouldn't be an unreasonable suggestion.