Sch 15 para 35
Where, after land has become vested in an acquiring authority under paragraphs 6 to 8, a person retains possession of any document relating to the title to the land, he shall be deemed to have given to the acquiring authority an acknowledgement in writing of the right of the acquiring authority to production of that document and to delivery of copies of it and (except where he retains possession of the document as heritable creditor or as trustee or otherwise in a fiduciary capacity) an undertaking for safe custody of it.