Was thinking about this a bit more and i think any leaching (if any happens at all) will be dependant on at least a couple of things other than the type of plastic that the bottle is made of;
How long the shake/liquid is in contact with the bottle?
Temperature of the liquid? I'm assuming the warmer the liquid the more prone to leaching the bottle will be...
So for me the time is very short, as I fill the shaker from a steel water bottle thats kept in the fridge and then a few minutes to make the shake at most, before I drink it straight down.
But the next thing I do about 90% of the time, is tip into the empty shaker, my tea or coffee that i've just made and then swill it round before drinking it down again.
So thats about 250ml of hot drink thats swilled round, which cools it down a lot in the shaker. Since it's now cool enough, I then drink it down pretty quickly,
So I think the risk to me of anything from the shaker leaching into the Queal shake is really very small, but maybe I'm making it a bit higher by next swilling the hot tea/coffee. How much higher I have no idea and so I may still get a glass shaker…
Edit - another thought. In the fridge is yoghurt, milk, cheese, juice - all in plastic of an unknown type that are in contact with the plastic for days/weeks! There could've been water and some soft drinks too at another time.
Why am I concerned about Queal / hot drinks in contact with a shaker for a few minutes, when I dont worry about those drinks / foods