For the Judiciary that I have wrote about:
The independence of the judiciary, in that they must be independent and free from corruption and the criticism from other branches to effectively interpret law and protect individual’s rights, and how the US judiciary has more measures in place to protect this independence ie. judges being appointed for life, can't diminish their pay etc.
Separation of powers which you've already covered
Judicial impartiality
Constitutional impacts on the judiciary's power in protecting rights so, UK parliamentary sovereignty, US constitutional sovereignty and the powers of the US supreme court in terms of judicial review and being able to invalidate legislation which it deems as "unconstitutional", which helps protects the citizens rights guaranteed in the US Constitution.
I am not sure if this helps at all but it is just what I have revised for the Judiciary.
Does anyone have any revision or essay plans for government scrutiny??? or which past papers covered that topic I cant find any and have done no revision on that topic.