For 8 years I was OIC of a fire station that had an estimated 80,000 disused lead mine shafts within 5 miles of the station so this type of incident was commonplace. We set up a specialist Rope Rescue unit (after many years of improvisation) and had unimog, sheerlegs and all the kit necessary to carry out this work safely. To be fair it was mainly animal rescues on which we honed our skills.
One of the biggest hazards is an irrespirable atmosphere in the base of the shaft, through a build up of CO2, CO, methane etc. Not many brigades carry monitoring equipment as a matter of course. We didn't for many years. If the casualty is alive and conscious then its a fair bet that the atmosphere will support life and a successful rescue is likely. The difficult one is where the casualty is out of sight and or unconscious.
I remember a very tragic incident on the station patch during the construction of a large reservoir, where one morning a construction team arrived to continue work in a shallow service shaft about 16 ft deep. Unbeknown to them a build up of CO2 had occurred in the base of the shaft over the weekend and the air was irrespirable. The first man on reaching the bottom of the ladder was overcome and collapsed. One by one three of his mates each descended the ladder, each with the intention of trying to effect a rescue and one by one each was overcome at the base. Heroes all but what a tragic and unnecessary loss of life. The youngest member of the team was the wisest and rather than descending to his death ran to the site office to raise the alarm. Sadly it was too late to save those brave men.
I do not know the details of the tragic event in Scotland but let us not overlook the the difficulty and hazards of descending into a confined space hanging on a rope especially if you have no evidence ofthe condition of the air.