This is the offending gap:
Since the day of disaster, I have made some progress.
On Wednesday, my friend Ben lent me a magnet that he had extracted from an old hard drive (don't ask). Thanks to how it was packaged, it had the valuable property of providing a strong magnetic pull along one plane, with far less magnetism in other directions. This gave me confidence I would be able to lower it down the lift shaft without it sticking to the sides.
This is the magnet:
The magnet is hidden between the two triangular-shaped pieces of shiny metal.
Full of confidence, I tried to use the magnet on Thursday evening. Unfortunately, even given its casing, it still had too much of a tendency to stick to the sides of the lift shaft and I didn't want to get it jammed.
I was ready to give up.
On Friday, I joined a conference call where I was due to talk a client through a project plan for a piece of work I am hoping they will engage us to assist them with. I was somewhat surprised when the first question I was asked was "have you got your keys back yet?"!
A useful conversation ensued and the questioner, Martin, pointed out the rather obvious (in retrospect) fact that I could stick the magnet on a rigid pole to give myself far more control. Perhaps all was not lost after all!
I couldn't try this out last night as we had friends over for drinks. Upon arriving back at home after lunch at a friend's today, however, we stopped to say hello to the porter. By chance, it was the same one that was on duty when I first lost my keys last week.
He amazed us by going into one of the back rooms and bringing out a three-metre long piece of wood, with a screw sticking out of the end that he had obtained for us. Fantastic!
We now had all the pieces we needed... a sufficiently long stick, a magnet and time.
A couple of minutes - and several layers of parcel tape - later, the magnet was adhered to the stick and I was poking it through the gap.
The keys were back in my possession almost immediately.
Upon returning the stick to the porter, he told me he had called Otis during the week and they told him their standard charge for retrieving keys is £150. Ouch...
So, does anybody have any suggestions on what would be an appropriate way to show my gratitude?