That's lovely - do you mind me asking where that has been hidden away for the past thirty odd years? It's the kind of thing I dream about finding in the attic... It's never even been built up before - effectively brand spanking new. Wow.
Thanks for the nice comments! I don't know where the frame has been hidden all those years. Bought it at the Dutch classified Marktplaats for 120 euro (100 pound). Seems a good price to me .