Yep, that green one looks the same as the amethyst one at Cambridge (same diameter as well). It is a bit more flattened than mine but I think it is probably from the same source - whatever that may turn out to be
So does anyone recognize the colours as specific to any factory in particular - "kingfisher blue", amethyst and lime/moss green
BTW I did email Magnor to ask if they recognised it but haven't had any reply.