This is what I got:
It's a set of Reynolds playing cards, taken from a games compendium (so no box). The cards have square edges, no indices, and full-length pictures (or "one end courts" as they are more often known). The seller dated them around 1850, but they're earlier than that because they use a woodblock/stencil printing method that Reynolds modernised around 1840. The ace is a design called "old frizzle" which was used by all UK card manufacturers from1828-1862 as it acted as a duty stamp (basically, it was very hard to forge and the card manufacturers had to buy it from the official printer, so if a pack didn't have it then it was evading duty). I don't think my pack is that old, though, because Reynolds' designs were a little cruder back then; I think my pack is more likely to be between 1830 and 1840, when they polished it up somewhat.
I really, really like these. Now I have to figure out some way to store them that's not going to make them deteriorate...