Time-limit for block assessments: extensions and exclusions govern completion periods for search-related assessments and related persons. Time limits for completion of block assessments arising from searches or requisitions are twelve months from the end of the month in which the last authorisation for search was executed or requisition made; this period is extendable by twelve months where an information-exchange reference is made. A limited initial period while seized or requisitioned items remain with authorities is excluded, and multiple specified intervals (including court stays, information exchange, audit or valuation directions, valuation officer reports, certain approvals or references, and Board for Advance Rulings proceedings) are excluded in computing limitation; short remaining periods are extended to minimum thresholds and month-end.