Not Meadow Garden. I don't believe these are from any official range at all. I think these are early experimental things. The triangular black label puts the date between '78 and '90, but these are not of any formal shape or colour pattern that went into production.
At the studio, there was a shelf in the shop called "the makers' shelf", through which the glassmakers and apprentices could make and sell things they'd designed and made themselves. These might have been from that, or perhaps were trials made by the Michael, Tim or Jonathon themselves.