This is an L2A2 baton (ie a rubber bullet) mismatched with an L3A1 CS case.
The CS case is difficult to find, the batons fairly common. Together certainly not worth £175 plus postage, but that is what someone paid, and the under bidder must have thought it was worth bidding £170 for.
https://www.ebay.co.uk/itm/Troubles-Rubber-Bullet-1970-039-s-Bogside-Derry-/193871762216
The CS case is difficult to find, the batons fairly common. Together certainly not worth £175 plus postage, but that is what someone paid, and the under bidder must have thought it was worth bidding £170 for.
https://www.ebay.co.uk/itm/Troubles-Rubber-Bullet-1970-039-s-Bogside-Derry-/193871762216