I picked this up a while ago, thinking it was a Davidson 643 in blue pearline, but all of the 643 pattern pieces I have seen have a different star pattern on the base, like this one:
http://www.cloudglass.com/VictorianDishes.htm (top image) rather than the long-rayed star on mine.
Can anyone confirm or deny it as the 643, or suggest a possible maker if it's not Davidson, please?
Incidentally, Christine had a look at it when she was here a few weeks ago and she, like me, initially though Davidson 643, but we are puzzled about the base pattern.