I suggest you have a look at Purition.
They do several different flavours of shakes in two basic forms, one is whey based, and the other vegan. No additives that are not natural.
Not cheap! So I suggest you shop around. Sometimes Amazon sellers undercut each other...
You add your (nut) milk of choice.
https://www.purition.co.uk/
Amazon can also be a great source of different brand names that crop up when you are searching for something else. I saw a pea protein shake on there recently, but cannot remember the name of it, I am afraid!
Ed to add: the brand name was 'Pulsin'