Andrew - the entry was added as a result of the Land Charges search result that accompanied the application to register the property for the first time in 2009
Land Charges are a means of registering such an interest with regards unregistered land/property It is not the case that someone can register such a charge without supporting documentation
To cancel the entry please lodge an application in
form CN1 which must be accompanied by a cancellation certificate as issued by Land Charges with regards the land charge itself - see section 5 of
Practice guide 63: the land charges registers and agricultural credits register: registration, official search, office copy and cancellation - GOV.UK
I note that the issue re the land charge was raised with the solicitor who acted for the owner in 2009 and correspondence was issued to him by post at the time