The non-Dixon transfer has some easily identifiable flaws. There is a small dot just beneath the letter 'P' (click on the images to enlarge), which reproduces on all three plaques. The engraver appears to have slipped while drawing the serif on the first letter 'R', which lurches upwards. The last two plaques share some additional flaws (implying they were made later), e.g. a dot below the second letter 'P', a dot just above the gap between the letters 'O' and 'D', and a small dash inside the letter 'A'.
If the Middlesbrough impressed plaque was made before 1840, and the Carr impressed plaque after 1860, what happened in between? The Dorman Museum has no record of the Middlesbrough Pottery producing lustre items. And note, the London mark above in Duce's guide is only 'attributed' to Middlesbrough. So more research needs to be done to firm up the Middlesbrough attribution. If you can fill in any gaps, please get in touch.