I see what you mean and I did notice the partial lettering above the AB; what I didn't make clear is that I think it is the top half of the GG mark as seen on the others. If you look to the right side of the cartouche, you'll see the line go up and then cut sharply to the left and then up again as with an overstamping.
But it wasn't only the mark that suggested to me that it was the same maker; it was also the style, particularly the dimpling on the top which features on all three of the jugs here. Is this a common feature? From the few jugs I've seen, I'd say no.
I liked your point about poorly struck hallmarks Tom and found a helmet cream jug by Peter and Anne Bateman from 1794 on Daniel Bexfield's excellent site.
http://www.bexfield.co.uk/01/d257.htm
It perfectly demonstrates your second paragraph; perhaps not only were the assayers more experienced, but their dies were of better quality. Though, having said that, this year I visited an abandoned jewellery factory (now a museum) in Birmingham which used all of its dies for the 80 years it existed. Link at bottom of page.
With this Bateman jug you'll notice that the maker's mark is punched horizontally; it might turn out that all such examples of this pair's work was stamped thus and so rule them out as the original makers of the first jug in this thread.
You'll also notice the workmanship is far superior than the three we've seen so far: for example the double reeded lip instead of a cut off edge, and the reeded handle instead of plain.
It's hard to believe the maker of this jug could be the same as the other three.
Miles
http://www.birmingham.gov.uk/GenerateCo ... NU_ID=1763
.