Hi,
definitely Not Monart, by guess would be possibly for Elwell - they were made by different glass companies including Nazeing and also I believe S&W.
The colours are unusual altogether but they are all known colours for Elwell pieces though normally just in one colour.
I doubt very much GreyStan.
Do the bubbles have a halo of colour around them when held up to the light?
good luck as many of these posy bowls / vases are difficult to attribute exactly, though yours looks like a better quality one.
Roberta