I had wondered who made these vases, so thanks all. I notice on the blue ones that the area of about 5mm below the rim is much more obvious than the clear ones. It almost looks as through it's been crimped in some way.
I recently saw some for sale in a Bristol retro shop, labelled as "Whitefriars Reproduction" which was quite horrible. They would be lovely little vases, if they didn't feel rather like heavy plastic.
Stu.