It's difficult to see if this is a Ariel brake plate, it could be something else.
Now the wheelspindle can not be taken much more backwards to tension the chain as the anchor is in the way.
If you turn the brakeplate clockwise towards the position it should be, the brakearm will be below the wheelspindle where it should be.
I think the brakearm itself is from a later model frontbrake, but if it works o.k. then use it.
I see that the rear stand has it's spring on this side, Ariels have it on the other side, the spring abutment on the frame is a later addition.