Face it, if the constitution is "whatever the prevailing political elite class says it is", then you don't have a constitution.
The Brits have nothing.
> The Brits have nothing.
There are words in the British constitution as well. Acts of Parliament that define how the Parliament and the courts function are constitutional laws, such as the Parliament Acts of 1911 & 1949 and the Constitutional Reform Act 2005. If we are going by words, there are a lot more words in these multiple constitutional documents than in the constitutional documents of many countries that only have one such document.
Neither the monarch, nor individual Members of Parliament, are above all limits under UK law.