No, you only need the english one as our exam covers the other subjects.
I took it just before Nats shut everything down, i was about to apply...
The exam is not long, i think it was 3 hours. You can take it in almost every school, as when, i don't really know. You should contact some of them and sort something out.
Yes i'm in the process as well, waiting for a reply....
On the online test i think you have some mental maths and some basic checkings, i don't know much more.
Hopefully, i'll see you there.