Dude, if it ain’t written, it don’t count. That 1688 thingie, IIRC, was an act of Parliament. Which can be undone way more easily than our Constitition, for example, can be amended.
Generations of British constitutional lawyers would disagree with you. Most of it is written, anyway: just not in a single document.
The multi-faceted British Constitution can be distilled into a single sentence:
Nothing may be done which Parliament cannot undo