Dag Margreeth,
Yes I do speak Dutch, born & raised just north of A'dam but left the country some 30 years ago or so. I'm starting having difficulties with the language now
I have lived in the UK for several years and now here in french speaking part of Belgium since 2000.
I'm adding a sketch of your vase by Dias, unfortunately I haven't found a catalogue image or reference in a book at the moment, but I'll continue searching. The sketch shows this model as a bit more plumb and 'heavy' on the eye, but it is a sketch of course and scanned perhaps a couple of times, so the shape might be slightly different from the real thing.
This model comes from a period in which 'Les Tordus' range was introduced. Large and heavy freeform pieces in bright colours, each the weight of a dead donkey. A production which was very popular at the time but unfortunately 'milked' by management in the 60/70's, resulting in one of the first bankruptcies in the 2nd half of the 20th C and a huge amount of these pieces on the market, you still see them everywhere today. I'm sure you have come across them in the past, bright blue, pink, green and yellow.
Your vase is slightly different with the applications wrapped around the body of the vase which makes it stand out a bit from the mass, i haven't seen this shape often but it is still part of this period and production.
Mvg,
Anne.