Joost — Several more thoughts ...
1. While the Weights & Measures Office location does not directly give you the manufacturing glassworks, you can make an informed guess. Wood Brothers of Barnsley were world leaders in pharmacy and laboratory glassware, also, without question, our most successful glassworks at exporting to the difficult USA market. I'm fairly certain that there wasn't a Weights & Measures Office in Barnsley, so York, covering the parts of Yorkshire that other Yorkshire Weights & Measures Offices didn't reach, was probably their office. So, all in all, more than an evens chance that your 545 measure was made by Wood Brothers.
2. As with all engraved glass, blanks may have been bought by an engraving operation, so your City of London measure could be City of London engraving on a blank from elsewhere. So both of your measures could have been made by Wood Brothers of Barnsley!
3. I'm a great believer in exposing young children to as wide a variety of number and logic experiences as possible, particularly today, when the best mathematicians don't become schoolteachers. This includes measuring and calculating length, area and volume, number games like cribbage and dominoes, games of logic like draughts and Rubik's cube, and experience of as many number systems as possible, particularly bases 10, 2, 12 and 16. A collection of relatively inexpensive measures in a variety of units could be a great asset in this.
Bernard C.
