Query re Symbol on LR Title Plan

Please can you advise what the "pin" mark on a boundary indicates. I'm used to T and H boundary indicators but can't find anything on the LR web site or a key anywhere to tell me what this symbol means. Extract LR Title Plan attached. Thank you

Catherine - it's an Ordnance Survey marking used as an indicator for where field numbers' and/or acreage extend to. Their limits effectively. It's not a HMLR marking or indicator so has no relevance re the registered information