The use of individual columns (type bit) to indicate the sub-type (Person or Organisation) is really awful. It does not cater for sub-sub-types (e.g. different types of Person). It is not extensible without adding a new column (type bit) for each new sub-type. It requires table constraints to guarantee that each row has exactly one type flag set.

I suggest that the type column be a computed column using an expression involving the schema of the xml (ideally) or the elements of the xml (if no schema). The standard help pages for xml have examples of doing this.