Texture's absolutely right - I've not seen one with a wavy rim before though, or one this short.
This expression
"made on the post"
is one which should really be
confined to the bin.
An initial gather of glass is blown, which forms the rim/neck, then the bubble is partially cased in more glass, which is then put in the textured mould. There is no other way of producing these pieces. I've discussed this with Ron and he agrees.
I'm not sure where your blue streak actually is.
Is it the bit
in the glass, swirling around the outside of the vase in the last picture?
That bit looks, to me at any rate, like one of the "escaped" trails of silver salt gas, which has ended up inside another casing - it can give this effect.
I don't know if you're wondering if it's some of the single cobalt blue pot which was melted at Mdina, as in the faceted inside-outs. I think I might need to get my mitts on it to tell.
Blue and white charger? IoWSG? I'd love to see it!