:huh:
I'm not sure at all!
Definitely not Isle of Wight Studio Glass, because they use coloured enamels, rather than colour melted in the pot.
The applied foot really confuses me. The browny purple does look right-ish, if the colour is in electric light-bulb sort of light, but it's hard to tell really, it looks a bit too red, I'd need to get my paws on it. The silver chloride does look right-ish, but I think other folk were also using this. I'm not convinced by the foot in conjunction with the broken pontil, and the button rim looks a bit tall for Michael Harris early period, though I have a couple of post-Harris perfume bottles in spirally striped tortoiseshell pattern with a similar rim - though these are very heavily cased.
What sort of colour is the clear glass? A good clear clear or is it a bit greeny or yellowy?
I'm afraid you may have to wait for Mark Hill to comment. My guts say not Mdina, but I may be wrong. It's too hard to tell from pictures, I'm afraid.