You wait 20 years to get your hands on one, and then two come along within a couple of months. Recently picked up this black glass 1810 - 1820 example to go with the green 1820 - 1830 one from last year.
These usually have very whittled embossing, hard to read as though blown into a very cold (or very old / worn) mold. This one has crisp embossing unlike any other of the type I've seen. It's a bit faint towards the base on this side, although all still readable (Sold by / R.Johnston / 15 Greek St Soho / London).
.... and here it is with the one picked up in October. Almost identical embossing, but on the green it's in 4 lines equally spaced around the bottle, and on the black it's seven lines, 3 on one side and 4 on the other.
Beautiful examples! Do embossed soda/mineral waters run any earlier than those two in the U.K.? Definitely should not be "cleaned" -- the glass has all the character left on it from history.
Outstanding acquisitions, sir! I don't know how I missed the first round of this thread. The patination on the first is absolutely killer.
Lemme axe you about the newest, with the early part of your date range, wouldn't this be within the very first few years of aerated waters bottled in Britain?
If you are so inclined, I'd love to see more photos, please.