FWIW, I am not claiming the law to be right or just, but it _is_ the law as it currently stands. Also, prior to 1994, GCHQ operated entirely outside of the law (hence the Act's wording "There shall continue to be [GCHQ]"; for a long time, the existence of the agency wasn't even publicly acknowledged), so in some ways it is a step towards respecting the rule of law.
Also, strictly speaking, the King is above the law - the Monarch is the source of all law, and even Parliament acts through that power in its activities: https://en.wikipedia.org/wiki/Queen-in-Parliament
> technically the queen is above the law as she is sovereign and the source of all law
What rubbish. In the UK, Parliament is sovereign. The British monarchy can be entirely removed by an Act of Parliament. Not only is it sovereign, but it cannot be bound by any previous Parliament.
Your fake facts portray the UK as an absolute dictatorship.
The emphasis on OP's quoted line should be on _technically_.
A bill has to proceed through Royal Assent by the Queen before it becomes law [1]. It just happens that she is always timely with this duty and always agrees with Parliament.
Also the government's executive power is primarily through Royal prerogative [2]. _technically_ the Queen could exercise these powers herself for her own benefit.
The "checks and balances" that keep the Monarch from abusing these powers are a combination of tradition, facing the wrath of the British people and precedent set by what happened last time a monarch attempted to abuse royal prerogative [3]
The leading text of Parliament sovereignty is Dicey, and its principle are considered to form part of the uncodified Constitution. It succinctly explains that:
> Parliament means, in the mouth of a lawyer (though the word has often a different sense in conversation) The King, the House of Lords, and the House of Commons: these three bodies acting together may be aptly described as the "King in Parliament", and constitute Parliament. The principle of Parliamentary sovereignty means neither more nor less than this, namely that Parliament thus defined has, under the English constitution, the right to make or unmake any law whatever: and, further, that no person or body is recognised by the law of England as having a right to override or set aside the legislation of Parliament.
Note the use of the phrase "King in Parliament" - all law making authority derives from the historical powers of the Monarch, whereas the Lords and Commons guide and use that power. This can be seen in how UK Acts of Parliament begin "BE IT ENACTED by the Queen's most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons" - the Act is _enacted_ by the Queen, with the two Houses advising and consenting to the use of that ability.
Now it's possible that the role of the Monarch could be removed from the process, but it would arguably by one of the biggest fundamental _technical_ (not practical) changes to the British constitution in hundreds of years.
But if the laws are written so that they don't apply to the king in the first place of course the law is just.