Are the Weeping Angels coming to Doctor Who spin-off Class?
Or has someone just been messing about in the props cupboard?

Doctor Who spin-off Class could feature an appearance from the scariest monsters in the Whoniverse – either that, or the actors have just been messing about in the props department...
Fady Elsayed, who plays one of the pupils in the Young Adult series about Coal Hill School, posted a snap of himself with none other than a Weeping Angel...
https://twitter.com/iFadyElsayed/status/757513436217614337
Now, Class is currently filming in the very BBC studios in Cardiff where Doctor Who shoots so it's reasonable to assume that they share a props department. And if you had the chance, you'd be in there rummaging through the stuff, right?
So it may be as simple as that.
On the other hand... it's a Weeping Angel! Bring back the Weeping Angels!