A method of installing a double ended distributed sensing optical fiber assembly within a guide conduit. The optical fiber sensing assembly has a first elongate section with a first proximal end and a first distal end, and a second elongate section with a second proximal end and a second distal end. The method includes providing a nose section having an outer width less than about 1 cm, which interconnects the first proximal end to the second proximal end such that light transmitted along the length of the first elongate section is transmitted via the nose section into the second elongate section, inserting the nose section into the guide conduit such that the nose section moves through the guide conduit ahead of the first elongate section and the second elongate section; and connecting the first distal end and the second distal end to a light transmission and receiving unit.