In 1835 Apsley Pellatt gave evidence at the Excise Report (Thirteenth report - Glass)
See page 126 - brief mention of them making coloured glass and the factory's inability to experiment or even make for example copper red glass due to the regulations of excise preventing any chance of success:
https://www.google.co.uk/books/edition/Parliamentary_Papers/GU0SAAAAYAAJ?hl=en&gbpv=1&dq=apsley+pellatt+foreign+glass&pg=PA125&printsec=frontcoverInteresting given the tax wasn't repealed until 1845, so if they were having difficulty making coloured glass in 1835 due to the requirements of when to open and close the pots and the tax excise as well, and these bowls were apparently made in 1837 ...
In addition to this, at the very beginning of his evidence (see page 120) I read it that he says he has given up manufacturing glass but continues to 'trade' glass? He says a little later in the evidence that if the tax was repealed he would recommence making glass immediately.
The tax wasn't repealed until 1845. The bowls apparently were made for the 1837 banquet at Guildhall, so ? IF the bowls had come from Pellatts (just a possibility given the similiarity to the Medicien shape of the finger bowl in the Collis printed pamphlet) in 1837, did he start making glass again in 1837 or was he trading imports?
If that pamphlet printed by M & Wm Collis was produced in 1841-1843 what were those articles for sale? Were they imports from France? or Bohemia? that he was selling.
In 1841 he did deposit a 'series of articles' into the Royal Polytechnic Institution. Were they articles he'd made? or were they 'examples' of a variety of glass finishes to show the designs and colours and decors as examples?
By the way, there are pages of evidence from him on the amounts of tax they were paying and the impact on their ability to produce. Makes fascinating reading as to how tied these makers hands were and how much these taxes cost them. Not just in money, which was huge, but also in form filling, extra hands necessary to be employed, the 'overseeing' of the excise inspectors on their premises etc etc. The impact was enormous.
Not surprising Bohemian glass was so advanced in colour at that time and by comparison.
The damage these taxes did to the trade in this country seem phenomenal. For one example it seems to me, from what I've read here and in other reports, the advancement of lens making for opticals, telescopes etc was lost to Germany and France. Opticals a very important industry for glass developement at that time.
Seemingly every other competitive country had better opportunities to produce in all the various sectors of glassmaking v the UK.