All apart from the singular fact that Tone BLiar promised us a sort of Bill of Rights - like he promised us a lot which never happened; Heh! Politician's promises, right? As reliable as one of Alan Sugar's warranties! - Magna Carta set out the rights of the
Barons from the King, not the serfs.
Magna Carta did, however, commence the process whereby the common man might expect a little more than simply existing as a feudal possession of his leige lord.
Magna Carta did, however establish certain precedents from which later, flowed various principles of law, which were expanded, eventually, to imrpove the lot of the commoner.
The later English Bill of Rights was far more critical to the common man.
http://www.unlockdemocracy.org.uk/?tag=magna-carta
So my conclusion is that not only is these people's history flawed, they are seeking my tenner under false colours, thus sadly, No Deal!