oooh, I'm very glad this has generated such a lively and interesting discussion and thank you so much to you all for taking a look and giving information. I bought it to do precisely that

I have nothing else like this, I don't collect pressed glass, but I do read others posts and when I found it I didn't recall seeing anything like it before (I probably paid way too much for it as well, but having not bought anything much recently I thought why not).
I'd read quite a few posts on malachite/slag/milk/ marbled opaline (and then vitro porcelain after Paul's post) and just got incredibly confused about what it actually is. It is turquoise, it appears to be a form of translucent opaline glass and it does have fine white swirls and streaks in it. You can actually see a very fine thin clear gap between the white streaks and the blue glass on some swirls, so it sort of looks like they didn't mix the turquoise properly, rather than looking like the marbled glass I've seen advertised as 'slag' glass where the white streaks are more defined and pronounced.
Thank you to all also for taking the time out to go through books and check details for me on maker and substance of glass - I really appreciate that.
Sue and bfg - bfg yours seems to be the same as mine

I am all over the place at the moment, but I'm pretty much sure it is a goat

(and to me it looks like Billy Goat Gruff lol) it is really detailed and well modelled. But I will now do some searches on Pan/satyr and mythological creatures and report back.
Ken thank you for doing that, and I will email the contact you gave and see what might transpire. I'll post back.
Edited to add -
I found this info on malachite/pressed glass colours from the site 'pressed in time'
http://www.pressedintime.com/Colours.htmand I have looked up Satyr and Pan and it seems to be a characteristic (please do correct me if I'm wrong) that they have 'partly human-like' facial features, whereas the goat on my goblet is definitely animal but with no hint of human

m