The brake mount arrived very quickly from Gaerlan Custom Cycles and the owner was very helpful with my questions along the way. Highly recommended!
A picture of it is below. It looks like it will fit quite well on the trike. My only issue will be that my wheel lock (similar to this) mounts on the other side of the frame where the brake mount will be. The top centre bolt of the brake mount will interfere with the current location of the lock but pretty sure I can get around this though by not having the lock sit flush with the frame.