Thanks stamfordman. I'm not sure of the PCN# and vehicle reg, they're blurred out. If it matters I can find out from her. She's definitely the registered keeper, I think she received the NtO around 18 Oct.
(As far as I know a property guardianship is basically an arrangement where you live in a disused building, an old school or council building etc., for greatly reduced rent in order to protect the building from squatters and for insurance purposes)