I spent a long time on the problem and actually managed to both diagnose it and also determine that it wouldn't be easily solved. I was stil there at 7pm. As it happens, though, I was not alone. The programme manager of the project I'm working on came along to provide a bit of company/moral support/attempts to remove problems. It was an act of solidarity which was appreciated and timely.
In the end we did our best to make the kit work and I think things will have been just about good enough for the major rush they'll be having over Christmas.
I ended the year doing the sort of job that was quite different to how I started the year. It wasn't all pondering and doing little. It was taking on a direct challenge and doing my best. That's sort of good.