A solo trip.
At the current end of Merlin's, attended to widening the narrow fissure to make for more comfortable digging. 6no. holes, plus an extra one for the trimmings, on either side of the opening. Spent some time making sure the holes were well-stemmed. Then, a steady retreat, reeling-out the wire, stopping at Stal Bend. All was good.
There should be stuff to clear on the weekend. Hopefully, someone will be able to rake-out the debris blocking the narrow fissure and see whether it widens, or, if there's any draught.
Exited the cave into a warm, humid evening.